Austad (1993) compared senescence in mainland and island opossums. Island opossums lived in an essen-tially enemy-free environment
He found that island opossums tended to live longer and that this increased longevity was paralleled by a de-crease in age-specific decline (breakage of collagen fibers). Age-specific fertility also followed the same pat-tern. Why do these results fit the predictions of the mutation accumulation or antagonistic pleiotropy hy-pothesis?
a. Older individuals on the mainland contribute less to reproduction than on the island.
b. Older individuals on the mainland contribute more to reproduction than on the island.
c. Without predators, individuals experience less stress, which corresponds to a lower rate of living.
d. Without predation, individuals get older and can acquire more late-acting mutations.
D
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a. oxytocin b. prostaglandin and DHT c. prolactin d. testosterone, AMH, and DHT e. Wolfian duct inhibitors
Creative destruction refers to the withdrawal of ________ from declining areas and activities for use in new areas and activities
A) capital B) building materials C) culture D) political ideas E) culture and political ideas
An excitatory postsynaptic potential
a. is only one of several types of graded potential. b. has a hyperpolarizing effect. c. will drive the membrane away from its threshold. d. is summed with an inhibitory postsynaptic potential at the input zone of a neuron in a process known as synaptic integration. e. help keep the membrane at resting membrane potential.
Conjugating ciliates exchange a pair of haploid micronuclei that undergo mitosis as a diploid micronucleus, while the macronucleus in each
A. divides by meiosis. B. disintegrates. C. is expelled from the cell. D. shrinks and becomes diploid micronuclei. E. fuses with each other.