You are presented with the quiz "Something eaten by humans have varied what?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "algae have varied life cycles" and "some red algae are eaten by humans". So, what's the best answer to the question?

OPT: [-] story times. [-] commutes. [-] temperature. [-] Plants growth. [-] energy usage. [-] life cycles. [-] bedtimes. [-] layers of fat.
The answer is:
life cycles