Explain Adaptation Through Selection Practice Test

In a giraffe population, neck length varies because of heritable genetic differences. During a long drought lasting many generations, most leaves near the ground are eaten quickly, and giraffes that can reach higher leaves are more likely to survive and have offspring. Over many generations, the average neck length in the population increases. Which statement best explains how this adaptation developed through natural selection (not because giraffes “needed” longer necks)?

A cactus species shows heritable variation in how much water its stem can store. In a desert with long dry seasons, plants that store more water are more likely to survive and produce seeds. After many generations, most individuals in the population have thick, water-storing stems. Which statement best explains this adaptation through natural selection?