Acell membrane is very specific about what it allows across. How does this help the cell? A. Transport proteins allow only enzymes to pass through the membrane.
B. It is better for the cell if most molecules are prevented from entering
C. The cell works better when it contains fewer proteins.
D. It helps the cell absorb as many different molecules as possible.​

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.