Male peacocks have tail feathers that make up 60% of their body length. during the mating season they fan their tails and shake these feathers in front of females. females evaluate the tail-shaking behavior as part of selecting their mate. which of the behaviors below is most likely to have been the original behavior that, through natural selection, resulted in this mate choice behavior of tail shaking?

1. flight
2. head movement to make eye contact
3. sound production with the larynx
4. involuntary muscle contraction like shivering
5. grooming feathers with the beak

4. how does a phospholipid behave in water? the phosphate head does not mix with water; the fatty acid tails do. the phosphate head and the fatty acid tails mix with water. the phosphate head and the fatty acid tails do not mix with water. the phosphate head mixes with water; the fatty acid tails do not.

Which of the following is not a defining characteristic of plants?

Which of the following describes a negative feedback loop? when the heart rate is too high, the body sends hormones that continually increase the heart rate higher. when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones. when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows. when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.