【单选题】❶In prehistoric times brachiopods were one of the most abundant and diverse forms of life on Earth: more than 30,000 species of this clamlike creature have been cataloged from fossil records. ❷Today b...
A.
rejecting an earlier explanation for the longevity of certain brachiopod species
B.
reevaluating the implications of uniformity among existing brachiopod species
C.
describing the varieties of environmental change to which brachiopods are vulnerable
D.
reconciling opposing explanations for brachiopods’ lack of evolutionary success
E.
elaborating the mechanisms responsible for the tendency among brachiopod species toward specialization
【单选题】Perhaps the most familiar plant movement belongs to one species of mimosa called the sensitive plant. Within seconds, it can lower its leaves and make its tiny leaflets close up like folding chairs. T...
A.
geographical distribution of plant and animal species