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What is tropism?

Tropism is the movement of a plant in response to a stimulus (an external force). The categories of tropism include:

Chemotropism—a response to chemicals, in which the plant leaves may curl up.

Geotropism or gravitropism—a response to gravity. Shoots of a plant are negatively geotropic (growing upward), while roots are positively geotropic (growing downward).

Hydrotropism—a response to water or moisture, in which roots grow toward the water source.

Paraheliotropism—a response by the plant leaves, in which they turn away from the sun in order to avoid exposure to it.

Phototropism—a response to light. A plant may be positively phototropic (bending toward the light source) or negatively phototropic (bending away from the light source). Main axes of shoots are usually positively phototropic, whereas roots are either negatively phototropic...

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1. Terms, Classifications, And Functions
   1. Who is known as the founder of botany?
   2. Who is Melvin Calvin?
   3. How many chloroplasts are there in plant cells?
   4. What is tropism?
   5. What are the parts of a flower?
   6. What is the best type of pollination?
   7. What is the first wildflower to bloom in the spring in the Northern United Stated?
   8. How are carnivorous plants categorized?
   9. Which flowers should be planted in the garden to attract hummingbirds?
   10. How does a bulb differ from a corm, a tuber, and a rhizome?
   11. What is wormwood?
2. Gardening And Agriculture
   1. What were some of the accomplishments of George Washington Carver?
   2. What are living stones?
   3. How are seedlings hardened off before planting?
   4. When is the best time to work the soil?
   5. Why should lawn clippings be left on the grass after mowing?
   6. How can squirrels be kept away from vegetable and flower gardens?
   7. Which flowers should be planted in the garden to attract butterflies?
   8. What is meant by "xeriscaping"?
   9. What does the term hydroponics mean?
   10. How are seedless grapes grown?
3. Trees
   1. What are the longest-lived tree species in the United States?
   2. How did the navel orange originate?
   3. Why do tree leaves turn color in the fall?
   4. Why are fall leaves bright red in some years and dull colors in other years?
   5. What is the difference between poison ivy, oak, and sumac?
   6. What is the tallest tree ever measured?
   7. What is the secret of bonsai?
   8. Does ivy cause damage growing on a brick wall?
   9. How are free rings used to date historical events?
   10. What are the distinguishing characteristics of pine, spruce, and fir trees?
   11. How much of a tree that is cut down is sold as timber?
   12. What conifers in North America lose their leaves in fall?
   13. Who introduced the gypsy moth into the United States?
   14. How can fruit trees be protected from being eaten by field mice?