Which of the following best describes how crossing over occurs during meiosis?
a. during prophase i, homologous chromosomes are lined up and pulled apart to opposite poles.
b. during prophase i, segments of chromatids are exchanged between homologous chromosomes.
c. during prophase ii, chromosomes overlap and sections of each chromosome switch places.
d. during prophase ii, sister chromatids trade places with each other before metaphase begins.

8) animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. d) a dog is getting hot in the sunlight, so he moves to a shaded area.