Roots, Water and Waiting: teacher key

How Plants Grow, grade 7 edition, written for 7th grade. Seeds can wait for years, roots pull in water, and trees trade with fungi. See how plants grow from the inside out.

Read the book. Print this page for the key.

Questions and answers

1. What is endosperm?
   • A starch-rich tissue around the embryo (answer)
   • A part of a flower
   • A kind of fungus
2. Why might seeds fail in soil that stays soaked?
   • They get too much light
   • They may not get enough oxygen (answer)
   • They lose their cold spell
3. What is typically the main force moving water up a plant?
   • Root pressure
   • Pollen
   • Transpiration (answer)
4. What did van Helmont conclude about the willow's weight gain?
   • It came from water alone (answer)
   • It came from the soil alone
   • It came from fungi
5. What does germination mean?
   • A leaf falling
   • A flower closing
   • A seed sprouting (answer)

Words

• endosperm: seed food store
• tropism: growth movement
• transpire: lose water vapor
• germination: a seed sprouting