单项选择题 In spite of the______frequently observed in honeybee colonies, individual honeybees are characterized by______to a surprising extent.

单项选择题 In contemporary usage, continents are understood to be large, continuous, ______ masses of land, for they are almost always separated by expanses of water.

单项选择题 Real body fluids, like those between our ceils, are less______than the model fluids that the researchers have used so far, and thus may introduce complications.