Chapter 9 - Plants - Life Science

The growth responses of a plant to its environment are called ________.

• auxins

• growth regulators

• hormones

• tropisms

A plant stem's growth response to gravity is called ________.

• positive gravitropism

• negative gravitropism

• positive phototropism

• negative phototropism

Which of the following plant organs demonstrate positive gravitropism?

• flowers

• leaves

• roots

• stems

What are the small chemicals made by plant tissues that affect how a plant grows?

• cambiums

• ethylenes

• hormones

• tropisms

Hormones cause plant cells to do which of the following?

• grow in size

• stop growing

• divide

• all the above

Which plant hormone causes fruit to ripen?

• abscisic acid

• auxin

• cytokinin

• ethylene

Day-neutral plants ________.

• are hybrids of long-day and short-day plants.

• do not have hormones to affect plant growth.

• bloom only on neutral days.

• are not affected by the length of day.

Poinsettias need at least thirteen hours of darkness to bloom. Poinsettias are ________ plants.

• long-day

• day-neutral

• short-day

• critical-night

Why do mosses need water for sexual reproduction?

• Falling raindrops must pop the spore capsules open.

• The gametophyte grows only if submerged under a few inches of water.

• The sperm must swim to the unmoving eggs.

• Water is used to carry the spores away from the parent plant.

What part(s) of a moss plant produces spores?

• the capsules

• the gametophyte

• the small, heart-shaped plant

• the soil