What is the name of the third germ layer that forms during gastrulation? (Figure 29-4)
a) primitive streak
b) mesoderm
c) embryonic disc
d) ectoderm
e) endoderm
Answer: b) mesoderm
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The Osteichthyes, or bony fish, make up about half of vertebrate species diversity. Their success is due to a combination of adaptations that include (select all that apply):
A. mobile jaws for specialized feeding. B. kidneys that allow fine regulation of water balance. C. lungs modified from swim bladders. D. metamorphosis allowing them to occupy distinct niches as juveniles and adults. E. paired, fleshy pectoral and pelvic fins.
If you were given the task of choosing a biological control agent for a reed from eastern China that has become invasive in the southeastern United States, what do you think would be the best choice? Consider both the effectiveness and the safety of the agent you be releasing.
A. A fungal pathogen from eastern China that specializes on the reed and can kill a plant in a few months. B. A generalist beetle, native to the United States, that can consume massive quantities of the reed in a few weeks. C. A nematode, native to eastern China, that specializes on the reed but can take up to two years to kill a plant. D. A caterpillar, native to the United States, that normally eats close relatives of the weed, but has been found in lab trials to perform better on the Chinese reed.
In honeybees, if food is closer than 50 m, scouts
A. perform a waggle dance about the food's location. B. perform a round dance about the food's proximity. C. perform a round dance about predation risk. D. look for other food. E. do not perform a dance.
In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned
to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen? a. The ratio of cell surface would decrease, compared to cell volume. b. The cell surface would shrivel. c. The surface area would remain constant. d. The number of membrane receptor proteins would decrease. e. The cell surface will keep expand