In a tropical habitat, a variety of hummingbird species use their bills to feed on flower nectar. If a population of hummingbirds enters a new habitat with an abundance of trumpet vine plants that have longer flowers, those
individuals with slightly longer bills will be favored in the new environment. Those hummingbirds with
medium-length and shorter bills are less successful. Which type of natural selection is at work in this example?

What do animals wth echolocation have in common other than echolocation

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.

Which of the following is the source of energy for photosynthesis? a.) glucose b.) chlorophyll c.) carbon dioxide d.) sunlight