Pressure develops inside phloem sieve tubes because:

a. osmotic uptake of water occurs when sugars are loaded into the sieve elements.

b. sieve elements lack a nucleus.

c. sieve elements are dead at maturity.

d. sucrose is a bulky molecule that exerts a pressure against the sieve tube walls.

e. All of the above are true.

Which of the following statements about plant spores is true? (Select all that apply.)

a. They are another name for gametes.

b. The multicellular gametophyte generation develops from them.

c. They produce the eggs and sperm that fuse to produce a new sporophyte generation.

d. They are part of the sporophyte generation.

e. They are much smaller than gametes.

Which of these is a gametophyte plant? (Select all that apply.)

a. petal

b. stigma

c. embryo sac

d. sepal

e. pollen grain

Endosperm is formed when:

a. two sperm from the pollen grain fuse with each other.

b. two nuclei from the embryo sac fuse with each other.

c. a sperm nucleus from the pollen fuses with the egg nucleus in the embryo sac.

d. a pollen grain lands on a stigma.

e. a sperm nucleus from the pollen grain fuses with two central cell nuclei in the embryo sac.

The difference between a seed coat and fruit is that (select all that apply):

a. fruit is always edible; seed coats are not.

b. seed coats are always hard; fruits are always soft.

c. seed coats develop from ovules while fruit tissue develop from ovaries.

d. dicots produce seed coats while monocots produce fruit.

e. fruit is tissue that develops outside the seed coat.

The pollen of gymnosperms generally is transported by _______, while the pollen of angiosperms generally is transported by _______.

Plants respond to gravity, touch, and the direction of sunlight through the _______ growth of roots or stems.

Plants in temperate climates make seasonal adjustments based on the relative length of the _______ they are experiencing.

A seed is a plant structure that includes a plant ______, its _____ supply, and a tough ______.

Of the following plants, which produce(s) seeds? (a) moss, (b) fern, (c) spruce tree, (d) orchid.

In their role as the male gametophyte generation of seed plants, pollen grains contain plant ____.