Some plants make toxic secondary metabolites, such as alkaloids, that discourage animals from eating them.
Correct Answer
True
True. Secondary metabolites are compounds not needed for basic growth, and many, including alkaloids, are defenses that make a plant harmful or unpleasant to eat.
Category: Land Adaptations
Question 2
Stomata are pores that open and close to control the exchange of gases and water vapor between a leaf and the air.
Correct Answer
True
True. Stomata let carbon dioxide in and oxygen out for photosynthesis, and closing them helps the plant conserve water.
Category: Land Adaptations
Question 3
Phloem carries water and minerals up from the roots, while xylem distributes the sugars made in photosynthesis.
Correct Answer
False
False. The roles are reversed: xylem carries water and minerals up from the roots, and phloem carries sugars and other dissolved nutrients throughout the plant.
Category: Land Adaptations
Question 4
Plant gametophytes produce their gametes by meiosis.
Correct Answer
False
False. A gametophyte is already haploid, so it produces gametes by mitosis. Meiosis happens in the sporophyte, when sporocytes divide to form spores.
Category: Plant Life Cycles
Question 5
Seed plants are homosporous, producing only a single type of spore.
Correct Answer
False
False. All seed plants are heterosporous: they make small microspores that become male gametophytes and larger megaspores that become female gametophytes.
Category: Plant Life Cycles
Question 6
In seed plants, the gametophyte is the large, dominant generation of the life cycle.
Correct Answer
False
False. In seed plants the diploid sporophyte is dominant, and the gametophyte is greatly reduced and develops within sporophyte tissue, as in a pollen grain or the female gametophyte inside an ovule.
Category: Plant Life Cycles
Question 7
Pollen protects male gametes from drying out and allows them to travel far from the parent plant.
Correct Answer
True
True. The tough wall of a pollen grain shields the male gametophyte, and wind or animals can carry it long distances, so seed plants do not depend on outside water for fertilization.
Category: Plant Life Cycles
Question 8
In bryophytes, the sporophyte stays attached to the gametophyte and depends on it for nourishment.
Correct Answer
True
True. A bryophyte sporophyte grows out of the gametophyte and relies on it for water and nutrients throughout its life.
Category: Bryophytes
Question 9
Bryophyte sperm reach the egg by being carried on the wind inside pollen grains.
Correct Answer
False
False. Bryophytes make no pollen. Their flagellated sperm must swim through a film of water to reach the egg, which is one reason most bryophytes live in damp places.
Category: Bryophytes
Question 10
Whisk ferns lack true roots and leaves and carry out photosynthesis in their green stems.
Correct Answer
True
True. Whisk ferns are reduced plants with branching green stems that photosynthesize and bear sporangia in small knobs at the branch tips.
Category: Seedless Vascular Plants
Question 11
Ferns reproduce and spread to new places by producing seeds.
Correct Answer
False
False. Ferns are seedless vascular plants that reproduce and disperse by spores, which are released from sporangia usually found on the undersides of their leaves.
Category: Seedless Vascular Plants
Question 12
Seedless vascular plants still need water for fertilization because their sperm must swim to the egg.
Correct Answer
True
True. Even though they have vascular tissue, plants such as ferns and club mosses have flagellated sperm, so most of them grow in moist environments.
Category: Seedless Vascular Plants
Question 13
A few conifers, such as larches, are deciduous and drop their needles in the fall.
Correct Answer
True
True. Most conifers are evergreen, but larches and the tamarack shed their needles each autumn.
Category: Gymnosperms
Question 14
Ginkgo biloba bears male and female reproductive structures on the same tree.
Correct Answer
False
False. Ginkgo trees are either male or female. Gardeners usually plant male trees because the seeds of female trees have an unpleasant smell.
Category: Gymnosperms
Question 15
The gnetophyte Ephedra is the source of ephedrine, a compound used as a decongestant.
Correct Answer
True
True. Ephedra grows in dry regions such as the southwestern United States and Mexico, and its sale is restricted because ephedrine resembles amphetamines.
Category: Gymnosperms
Question 16
In pines, each cone produces both pollen and ovules.
Correct Answer
False
False. Pines make two kinds of cones: small pollen cones that release pollen and larger ovulate cones whose scales bear ovules. Both kinds usually grow on the same tree.
Category: Gymnosperms
Question 17
Monocots usually have a taproot with branching lateral roots.
Correct Answer
False
False. A taproot with lateral roots is typical of eudicots. Monocots usually have a fibrous system of adventitious roots with no main taproot.
Category: Angiosperms
Question 18
Most flowering plants depend on wind rather than animals to carry their pollen.
Correct Answer
False
False. More than 80 percent of flowering plants rely on animals such as bees, butterflies, birds, and bats to move pollen from flower to flower.
Category: Angiosperms
Question 19
Flowers pollinated by moths are often white and open at night.
Correct Answer
True
True. Pale flowers stand out in darkness, so many moth-pollinated flowers are white and open in the evening when moths are active.
Category: Angiosperms
Question 20
Compounds from willow bark led to the development of aspirin.
Correct Answer
True
True. Willow bark contains salicin, a compound related to salicylic acid, which served as the basis for aspirin, a widely used pain reliever.
Category: Plants and People