What have we learned from fossil evidence about evolution? Select one:
a. It is an abrupt change.
b. The process is observable.
c. It takes place during one lifetime only.
d. The most complex traits are always selected.

Based on the observation that only male crickets produce a song, you hypothesize that a male's song is a form of communication to potential mates. you set up a simple experiment to test this hypothesis. in the laboratory, you place a male snowy tree cricket in enclosure a, which is adjacent to enclosureb. in enclosure b, you place other insects, one at a time, and observe their responses to the male's song. the enclosures are designed so that the two insects being tested cannot see or smell each other, but sound is transmitted from enclosure a to enclosureb.

Substances that can pass through cell membranes by diffusion include a. na ions. b. proteins c. glucose. d. oxygen.

Which environmental change would most likely result in bullfrog offspring that are able to store more water than bullfrogs in previous generations?