Grass. - Free Online Library Background Grass: From Seed to Mouth
Questions to discuss as initiating questions and/or as comprehension checks after completing this lesson on Grass.
* What do people have to take into account when planting lawns?
* Are there different kinds of lawn grasses?
* Why is grass important?
* Can you describe a grass plant?
* What are some ways to plant grass?
* We often think of grass as just for lawns. What other uses do grasses have?
* What are some names of grasslands around the world?
* Are there harmful grasses? What do these grasses do?
* Scientists have detected more grass than usual surviving the
winter in Antarctic. The grass signals a warming of this icy continent.
* Underwater grasses provide important habitat for blue crabs in the Chesapeake Bay.
* Grass is the common name for the family of grasses, designated as Poaceae. It contains almost 9,000 species of plants ranging from the 40-meter (130 feet) tall bamboo to the turfgrasses that most children think of when they hear the word, grass.
This issue introduces children to the idea that grass is important for Earth's health. Depending on the level, children will learn that people must take into account many factors when planting turfgrass. Lawns are important in the United States. The Lawn Institute estimates that there are over 31 million acres of lawn in the country. This is the
size of the New England states. Children also learn that animals depend on grass for food and shelter and that even people eat grass!
Like all plants, decorative turfgrass is important for Earth's health. As a plant, it takes carbon dioxide from the air and releases the oxygen that is necessary for animal life. It also prevents erosion by holding soil in place. A good lawn keeps homes cooler on hot summer days. It is estimated that an average lawn absorbs thousands of gallons of rainwater in a season and traps millions of tons of dirt and dust! Planting a Healthy Lawn
A lawn is really a big garden. It is made up of thousands of tiny grass plants. Homeowners have many decisions to make when planting a healthy lawn. It is important to know if the desired species of grass is right for the part of the country in which you live. Southern homeowners must plant warm-season grass. Their growing period is in the summer months. Lawns in the north need cool-season turfgrasses. These grasses grow better in the spring and fall. This is important because grasses flower and produce roots during their growing season. The climate must support the growing time.
Grass blades come in three basic textures: coarse, medium, and fine. Golf courses need a finer texture so golf balls can travel further! Many homes, particularly in the south, have coarser bladed grass.
Other factors that need to be taken into account when selecting a turfgrass are: the kinds of pests that might eat the lawn, the amount of sun in the yard, the type of soil, and the hue of green that is desired. With careful planning, people can find just the right turfgrass for their lawn garden. It is interesting to note that one of the favored types of turfgrasses is not even a native grass in the United States. Kentucky Blue Grass is native to Europe!
From Seed to Blade
Most grass is perennial meaning homeowners do not have to replant each year. However, some
types of grass are annual. Ranchers and farmers use annual grass during the times of the year when cattle cannot graze on perennial grasses because it is in a growing season.
There are four ways of planting grass: seeds, sod, sprigs, and plugs. Sowing seeds is a favorite way to plant a lawn because it is inexpensive. This does require a lot of time and attention. The soil conditions must be favorable and watering needs to take place on a regular basis. Sod provides an instant lawn, but many people do not take into account the necessity for proper preparation of thesoil. They spend time and money watering their new lawnonly to be disappointed when it dies because of poor soil. Plugs are smaller pieces of sod that can be planted, while sprigs are pieces of lawn that are ready to form roots and grow. Sprigging and seeding helps grass to develop strong root systems.
Once planted and fertilized, and the grass https://www.vocabulary.com/lists/283933 is growing, it needs to be mowed. Again, research about your type of grass is needed. If cut too short, the grass blades can not adequately perform photosynthesis. This means the plant is more susceptible to pest infestation and disease. Fungus can attack the grass. Encourage interested students to research grass in your area to learn more about proper mowing techniques. The necessity to ensure proper grass height is one which cattle ranchers must take into account. If animals "cut down" grass too much or eat during the peak growing season, pastures can be harmed.
Help students to see the many factors that need to be taken into account when growing grass.
A World-Wide Food
The many species of grass plants include the cereal crops of rice, wheat, corn, and barley. This means that the human race is dependent on grass for a large percentage of our food supply. Rice is particularly important. It is grown on every continent, even Antarctica, and is an important food source for global nutrition. On the whole, rice provides about 20% of the world's dietary protein.
Students may be surprised to learn that bamboo is also a kind of grass. Currently, botanists and biologists are working in the Wolong region of China to ensure survival of the panda's favored food, arrow bamboo. This writer was lucky enough to trek through this panda habitat and talk with the Chinese scientists working in the preserve. Currently, arrow bamboo is in the flowering stage in the Sichuan province. After flowering, there is a die-off of this species meaning pandas may have trouble finding their favored meal. Your children may read about this concern in news reports.
Other grass foods include Lemon grass, a native plant of India. This grass family ingredient gives Thai and Vietnamese dishes a unique flavor. It is also used in tea and can even be used as a scent in soap, perfume, and candles. Some people and companies are experimenting with
grass juices, and are selling a product made of the young grasses of the wheat, barley, etc. plants. They claim the vitamins and minerals are blood-building foods.
Vegetation: A Water "Barometer"
Important vegetation grows in and around water. Native grasses (species that have always inhabited a specific location) serve as useful habitat and food for many animals. Sometimes these species may not be true members of the grass (Poaceae) family. They have developed common names such as eelgrass or widgeongrass because they look like true grasses. Many fish need these aquatic grasses for breeding and raising their young. Water birds depend on grasses for food. Biologists use the health of aquatic vegetation as one indicator of eco-system health.
Grasslands
Throughout the world, there are different kinds of grasslands. Your students are likely familiar with the savannah in Africa. This "sea" of waving grass that is home to elephants, zebra, and wildebeest is not the only type of grassland on the continent of Africa. A savannah is distinguished by its climate. Savannahs are located in warm/hot areas where there is a concentrated yearly rainfall 50.8 to 127 cm (20-50 inches) that falls over a six to eight month period. The rest of the year is characterized by a period of drought. Southern Africa is home to temperate grasslands called veldts.
Temperate grasslands are characterized by less rainfall and distinct high and low temperatures in summer and winter. Besides veldts, other grasslands of this kind include the pampas of Uruguay and Argentina. Prairies of the United States, and steppes of eastern Europe. Various types of animals inhabit these eco-systems.
What's Being Invaded?
An invasive species is one that has been introduced in some way (human transportation, on animal fur, etc.) to a new location from its native habitat. These new species are harmful to the habitat of the new area. Cogon grass is a species of perennial grass considered an invasive in the United States. It also is a problem in its native habitat of Southeast Asia. It serves as a host plant for rice hispa, a pest that plagues rice growers. In the United States, cogon grass spreads rapidly and forms a thick mat of undergrowth. This serves as a barrier to natural plant germination. Its thick "carpet" hinders small animal nesting. Because it can grow quickly after fire, cogon grass is able to take over a habitat after such an occurrence. Unfortunately, many plant nurseries sell this invasive under the common name, Red Baron.
Students usually are fascinated by the concept of invasive species (maybe it's the name!). Encourage them to find invasives that may plague your area. Have students write questions they wish to ask your local agriculture agency. If you can't take a field trip, submit
your questions in writing. Perhaps some students may even do a phone interview with an employee of a government agency.
Level Pre-A
Main Concepts: Grass helps the environment by cleaning air and preventing erosion. People and animals eat grass.
Picture Activity
Ask the children if they can tell about the place WHY FLY is visiting. Have them use their senses to imagine what he may be experiencing. Lead them to a discussion about the picnicking children. Look at what the children are eating. It is rice! Tell them that rice is really a kind of grass. Look at the book about Pandas the girl is reading. It has a picture of a Panda eating bamboo. Tell them bamboo is a kind of grass, too. Draw their attention to the stream and talk about aquatic grasses. Ask children how grass growing in water can help animals.
Use the pattern of the sentences to read the paragraph. You may need to point out that grass starts with a capital letter in the first three sentences. Emphasize the blend, gr.
Vocabulary
Look at the lion. Have children say, "grrrr." After writing gr on the blanks, have children decode words by whispering them to the picture of the lion. Then encourage partners to read the words and use them in sentences before sharing the words as a whole group.
Math
Teach beginning study skills by encouraging children to circle each grass plant as they count. This helps them to keep their place. Check work to be sure children have correctly written 12, a difficult number for children of this age.
Weekly Lab
You will need grass seeds, cups, water, and a sunny ledge. Emphasize to children that scientists (botanists) need patience when performing experiments as they often have to wait for plants to sprout and grow. Keep track on a calendar when each seed begins to sprout. This will help teach days of the week and heighten awareness of time passage. Emphasize words such as hour, day, and week to help them learn these important math-related concepts.
Storytelling
Have children whisper stories to each other. Some classes may be writing stories and sentences. Encourage children to do so from the perspective of the little bug.
Puzzle
Not only is this maze a good way to improve sensory integration (see Science Weekly, Volume 21, No. 5--Zoos), but it also opens the opportunity to talk about grasslands of the world. See TN--BACKGROUND.
Bringing it Home
This activity may be done at home or in the classroom. Be sure to use cups that children may draw a face on after the grass has grown. We prefer Styrofoam cups.
Level A
Main Concepts: Grass helps the environment by cleaning air and preventing erosion. People and animals eat grass.
Picture Activity
See TN--Level Pre-A. Ask the children if they can tell about the place WHY FLY is visiting. Have them use their senses to imagine what he may be experiencing. Lead them in a discussion about what the people in the picture are eating and reading. Point out that the people are eating rice! Tell them that rice (and other cereals) are a kind of grass. Look at the book the girl is reading. It has a picture of a Panda eating bamboo. Tell them bamboo is grass, too. Draw their attention to the stream and talk about aquatic grasses. Ask children how grass growing in water can help animals. Ask them what animals they can find in the picture. Write the words eat, read, and stream on the board and point out the long sound of "e". Ask what they like to do in the grass.
After reading the story, talk about the many kinds of grasses. Point out that while we do not eat turfgrass, we do eat certain types of grass such as rice and wheat.
Vocabulary
This activity gives your first graders the chance to read more about grass, to discover the spelling of long e, and to practice their developing decoding skills. Depending on the skill level of your class, you may read chorally, in pairs, or individually. After reading, children could write the words on cards. They could sort these "e" words into 2 columns as shown below.
ea words ee words
cleans keeps eat green wheat seeds leaves need meal sheep feast To extend this activity, have children write their own long e grass sentences. You may want to list the following words on the board: stream, sea, beach, breathe, beak, beast, heap, treat, feed, need, sleep, free, geese, teeth, weed, creek, reed. For students needing further challenge, have them find their own "e" words in books and on charts.
Sticky Note:
It is important to point out that "ea" does say short
"e" in some words (i.e. great).
Weekly Lab
You will need to bring grass seed, soil, and cups. Use your class rulers or even nonstandard units such as Unifix[c] cubes to measure the grass. After you plant the seeds, be sure to label, water and no water. Discuss that botanists often have to be patient in performing experiments. As grass grows, use the opportunity to model how scientists keep organized data sheets. You may measure the growth and note numbers as a class. Have children make comparisons as growing continues. "Questions of the Day" may include, "How much more did the water grass grow than the no water grass? How did you know that?"
Ask children what happens in the hot, dry months. Do entire lawns die off? Why not? When you are finished, you may want to dig up the grass and compare the roots in each cup.
Math
Talk about the important function roots serve as part of a plant. Encourage children to look for three numbers that add up to ten. To extend this activity, have children draw their own grass plants and write questions about their "grass garden." Share the questions.
Writing in Science
Help children understand that, although their stories will be fiction, they can still contain factual components. Children should understand that many species use aquatic grass as food, shelter, and camouflage. It is an important for raising young animals as it provides a hiding place. Encourage children to close their eyes and whisper the story to themselves before taking pencil in hand.
Puzzle
Not only is this maze a good way to improve sensory integration (see Science Weekly, Volume 21, No. 5--Zoos), but it also opens the opportunity to talk about grasslands of the world. See TN--BACKGROUND. Ask children to discover what the names are for grasslands in different areas of the world.
Bringing it Home
See TN--Level Pre-A.
DID YOU KNOW??
Bamboo is a grass with a hollow stem.
Level B
Main Concepts: Grass helps the environment by cleaning air and preventing erosion. People and animals eat grass. It serves as a place for animals to live. Grass needs sun, good dirt, and water to grow.
Vocabulary
This activity reinforces the idea that there are many kinds of grasses, including those we eat! Encourage children to circle the word as they alphabetize it. This will allow them to see the word if an error is made.
barley rice corn sugarcane oats wheat Math
"Count the roots" helps children to understand the concept of multiplication. Some children may need to draw all the roots and count them. Others may count and recount the roots on the picture. Some children may be able to see the pattern and will grasp the concept.
To extend this activity, draw plants with differing numbers of roots. Ask various questions. Look at the pattern of 4s, 5s, etc.
Weekly Lab
This lab emphasizes the need for good soil. Surprisingly, many homeowners and even sod companies don't fully appreciate the importance of rich soil. Emphasize the comparative aspect of this lab to teach children that professional scientists must have their work replicated for others to accept their results.
Where in the World?
This puzzle introduces children to the idea of the scientific classification system by using the word, species. Children will discover the name of the bamboo that pandas love is arrow bamboo. See TN--BACKGROUND for more information about arrow bamboo.
Writing in Science
At this time of year, many of you are working on simple types of nonfiction paragraphs. Use the information in the article to have your students write a sequence paragraph about grass.
Puzzle
Use this activity to talk about harmful invasive grasses (see TN--BACKGROUND). Perhaps there are invasive grasses in your area. Buffalo grass (the solution to the code is a native grass and was an important food for the large herds of bison that once roamed the plains.
DID YOU KNOW??
Exotic is the term for a species that has been introduced to a new habitat but it doesn't seem to harm that new area.
Level C
Main Concepts: Grass is important for the health of Earth. People in different areas plant different turfgrasses There are four main ways to plant lawn grass. Various species of grass provide food and shelter for animals.
Vocabulary
Emphasize that children may look back at the information on page 1 of the student level to find their answers. Encourage children to underline the important information. This will help develop nonfiction reading skills.
Small squares of sod--plugs Plants put this into the air--oxygen Grass that grows in water--aquatic Plants take this from the air--carbon dioxide The washing away of soil--erosion Cool season grass grows in the spring and--autumn Grass is important for the health of--Earth
The Latin name is Poaceae.
To extend the activity, have some children find out more about the classification system. Use Multiple Intelligences and have children perform a skit, starring themselves as Carolus Linnaeus, father of the classification system.
Weekly Lab
Discuss with children that, in the scientific community, experiments may take years to complete. You may want to plant more than one cake pan of seed. See which variety prevents erosion best. Record the measurements on a data sheet and ask questions such as, "How many more centimeters did the plastic bug (or other small object) travel in the soil pan than in the grass pan?"
Math
Discuss with students the benefits of grasscycling. Explain that it is like recycling.
Grass Clippings Year kg per season)
1 104 2 208 3 312
4 416 5 520
Total 1,560 To extend this activity, have students compute the number of grass clippings produced over longer time spans. You could also vary the size of the yard. Find the size of your schoolyard and calculate how many grass clippings it produces in a growing season.
Where in the World?
Help children identify the countries/continents on the map. See TN--BACKGROUND for facts about grasslands around the world.
Puzzle
See TN--Level B. Students may trade papers and solve the new puzzles. You could even make a "book" of your class' native grass puzzles!
Writing in Science
Model for students what they, as grass, might say. Ask them to suggest facts that could be woven into their conversation. Encourage them to have a "back and forth" dialogue with the crabgrass. This will give them the opportunity to practice the correct use of
quotation marks.
Level D
Main Concepts: There are many species of grass to use and different ways to plant them. Because of the plant needs, care must be taken to learn about the species you have chosen. Grass is important to life on Earth. Its many functions include preventing erosion, providing oxygen along with serving as food and shelter for many animals.
Vocabulary
This activity gives students the chance to identify continents and countries along with learning more about the grassland biome. Practice using context clues by pointing out that the definition of biome is given in the paragraph. We have provided clues that will allow students to learn a fact about each grassland.
To extend this activity, have students learn more about one of the grasslands, as well as the plant and animal life native to the area, and report back to the class.
1. veldt 2. pampas 3. steppe 4. grassland 5. savannah 6. prairie Math
This is a fun activity to do on a warm spring day! Make sure that
all students have the same idea of what comprises a grass plant! A single plant may have more than one blade (leaf), such as shown in the diagram at the bottom of this page. Explain to the students what they should be looking for, and make sure they are all looking for the same thing. Suggest that students repeat this activity at home or at a park, or other grassy area.
Reminder: Mean is an average, median is the middle number in the order from least to greatest, and mode is the number that appears the most often. Encourage students to write their own story problems about their information.
Weekly Lab
It is important that the teacher/adult choose grass that is quite varied. A visit to your local garden store will be helpful in determining the seeds that are available in your https://www.youtube.com/watch?v=EHYPdVdcD_Y area. (Be sure to ask for donations.) You may want to get more than three types of seeds so you can compare many varieties. Share your results with the garden store. They may want you to make a special display for them in return for their seed donation!
Writing in Science
You can make the distinction with your students that native plants
are those that have always been in a specific environment, while invasives are brought to a new place and hurt their new surroundings. (Exotics are not native, but do not necessarily hurt the environment.) Discuss the ways a chain of events might hurt larger animals (i.e. mice can't nest and they serve as food for bigger animals. These animals might then disappear.)
Meet the Scientist
After reading the article about Dr. Beth Middleton, discuss with students the education a botanist needs. Have them imagine a typical day in the life of a botanist. Note that Dr. Middleton's father encouraged her to find a passion and to pursue it. Encourage children to think about their passions and how they might turn these into careers.
Level E
Main Concepts: Doing your research is important, even when it comes to planting a lawn! There are many species of grass to use and different ways to plant them. Because of the plant needs, care must be taken to learn about the species you have chosen. Grass is important to life on Earth. Its many functions include preventing erosion, providing oxygen along with serving as food and shelter.
Vocabulary
This activity gives students the opportunity to practice using context clues along with labeling diagrams. As an extension, have students look in reference material to find other grass plant parts and add these intricate details to the drawing.
Math
See TN--Level C.
Year Grass Clippings (kg per season)
1 157 2 314 3 471 4 628 5 785
Total 2,355 To extend this activity, have students compute the number of grass clippings produced over longer time spans. You could also vary the size of the yard. Find the size of your schoolyard and calculate how many grass clippings it produces in a growing season.
Weekly Lab
See TN--Level D. This level has the addition of the camouflage concept.
To extend this activity, take a trip to a local nursery and have students research the favored growing conditions of the turfgrasses of your area. Ask students to determine what type of turfgrass your city or town uses in the parks and public areas. Have them interview city planners as to why these species of turfgrasses were chosen.
Writing in Science
See TN--BACKGROUND--What's Being Invaded? Suggest ways invasives can be introduced to a new area: Encourage students to write fiction stories based on fact. This is a good opportunity for them to understand that often facts are woven into stories.
Meet the Scientist
See TN--Level D.
Grass
Did you know that grass is important for Earth's health? Like all plants, it gives off oxygen (ox-y-gen) and takes in carbon dioxide (car-bon di-ox-ide) from the air. It stops erosion (ero-sion) by holding soil in place. It can even keep a house cool on a hot day!
How Does Grass Grow?
Most lawns are made up of hundreds of grass plants. These plants are called turfgrass (turf-grass).
People in the south plant warm-season turfgrass. It grows in the summer. Lawns in the north have cool-season turfgrass. These grasses grow in the spring and autumn. During its growing season, grass grows strong roots and forms flowers.
Watching Grass Grow!
There are four ways to plant grass: seeds, sod, sprigs, and plugs. Seeds are a favorite way to plant a lawn. If you want grass fast, sod works best. You can unroll these mats of grass onto the ground. Plugs are small squares of sod. Sprigs come ready to form roots and grow.
Large grass leaves help the plant to make enough food to stay healthy. Good food means strong roots. When mowing grass, you must be careful to not cut it too short. If your grass is too short, insects might eat it and disease could kill it.
Eating Grass Is Not Just For Dogs!
Did you eat grass this morning? Most cereal crops like rice and wheat are grass! If you put sugar in your bowl, that sugar came from a
grass called sugarcane (sug-ar-cane).
Other animals eat grass, too. Pandas love to eat a type of grass called bamboo. Fish need aquatic (aquat-ic) grass to raise their young. Other animals needs water grass for food and shelter.
Many kinds of grasses keep our planet green and healthy!
Vocabulary
Use the information you learned on page 1 to fill in the correct words, below. Put one letter on each line.
Small squares of sod-- Plants put this into the air-- Grass that grows in water-- Plants take this from the air-- The washing away of soil-- Cool season grass grows in the spring and-- Grass is important for the health of--
Write the first letter of each word, above, on the lines below. These letters spell the Latin name of the grass family!
Weekly Lab
How does grass prevent soil erosion?
You need: 2 large cake pans, soil, grass seeds, water, sunshine, a
few small objects, and a ruler
Step 1: Put soil in both cake pans. Plant grass seed in one of the pans. Water it and put it in the sun.
Step 2: Wait for your seeds to grow. Botanists (bot-a-nists) need patience!
Step 3: When your grass is tall, put some small objects at one end of the pan. Put the same objects in the same place in the soil pan.
Step 4: Hold the pans and tilt them just a little. Pour water on the soil and grass.
Step 5: Observe what happens to the soil and the objects. Measure the distance the objects move in each pan.
Step 6: Record your results in your journal.
DID YOU KNOWP?
The study of plants is called botany (bot-a-ny).
DID YOU KNOW??
Kentucky Bluegrass is https://www.youtube.com/watch?v=EHYPdVdcD_Y a popular cool-season
grass in the United States. The catch is, it's not native to our country!
Math
Grasscycling helps make soil healthy.
Finish this chart to show how many kilograms of grass clippings a 94 square meter lawn produces over 5 growing seasons.
Why is grasscycling important? Many grass clippings find their way to landfills (land-fills). In the United States, many landfills are getting full.
This problem could be solved by grasscycling. To grasscycle, just leave your grass clippings on your lawn. Let them decay.
Think about this. A 94-square meter lawn will produce about 104 kilograms of grass clippings in a growing season. That's heavy waste!
DID YOU KNOW??
Grass clippings and yard waste may make up 25% of landfills!
A 94-SQUARE METER LAWN
Total kilograms of grass clippings produced YEAR per season
1 2 3 4 5
Total kilograms of grass clippings produced over 5 growing seasons Writing in Science
Crabgrass (crab-grass) is an unwanted weed in many lawns. It is much wider than turfgrass and branches out as it grows. Crabgrass turns brown at the first frost. People often put herbicides (her-bi-cides) on their lawns in the spring to stop crabgrass.
Imagine you are a healthy turfgrass plant. Crabgrass is trying to invade your space. What would you tell it? Get in as many facts about
"yourself" as you can.
Where in the World?
Grasslands are important to the health of Earth. They give food and shelter to many animals. Look at the map to see the different kinds of grasslands in the world. Find the names of these grasslands in this word search.
DID YOU KNOW??
A steppe is found near mountain barriers and away from the ocean.
DID YOU KNOW??
A veldt is an open grazing area in southern Africa.
DID YOU KNOW??
Invasive (in-va-sive) grasses are plants from outs de an area. They usually cause problems in their new place.
Puzzle
Grasses that have always grown in the same location are called native grasses. Crack the code below to find the name of a North
American native grass.
Find out the names of some other native grasses. Make your own secret code, then trade with a friend!
Weekly Resources Helpful Sources for Planning Your Science Weekly Classroom Activities
Recommended Resources
* Batten, Mary. Aliens From Earth. Atlanta, GA: Peachtree Publishers, 2003.
* Landau, Elaine. A True Book, Wheat. CT: Children's Press, Grolier Publishing, 1999.
* Morris, Karyn. The Kids Can Press Jumbo Book of Gardening. Toronto, Canada: Kids Can Press, 2000.
* Savage, Stephen. Animals of the Grasslands. NY: Raintree Steck-Vaughn Publishers, 1997.
* Thomsen, Ruth. Rice. Ada, Oklahoma: Garrett Educational Corporation, 1990.
Internet Resources:
Cogon Grass Information: http://www.nps.gov/plants/alien/fact/imcy1.htm
Information and classroom activities about wetlands can be found at: http://www.nwrc.usgs.gov/fringe/ff_index.html
Teachers will find information about how to choose a lawn grass at: http://www.ehow.com/how_4189_choose-lawn-grass.html
A cool interactive grasslands activity can be found at: http://www.missmaggie.org Open the big red button, look at the Herd of Elephants, Part 1 pack, click the compass and have your students play to learn!
A fun lesson plan about prairies can be found at: http://teacherlink.ed.usu.edu/tlresources/units/byrnes-literature/ jrees.html
The benefits of grass and information on grasscycling can be found at: http://www.turfgrasssod.org/lawninstitute/environmental_benefits.htm
Visit us online at: www.scienceweekly.com
https://www.thefreelibrary.com/Grass.-a0131130597