The coast of california on the western side of the state has a moist climate, while eastern side is a desert. it could cause the difference in: c. the west side is closer to the equator than the east.
hope this help
I believe your answer is C. incandescent bulb
In the 1800s, westward expansion brought settlers and their livestock into direct contact with native predator and prey species. Much of the wolves’ prey base was destroyed as agriculture flourished. With the prey base removed, wolves began to prey on domestic stock, which resulted in humans eliminating wolves from most of their historical range. Predator control, including poisoning, was practiced here in the late 1800s and early 1900s. Other predators such as bears, cougars, and coyotes were also killed to protect livestock and “more desirable” wildlife species, such as deer and elk.
A biome is defined as the large ecological area where the formation of plants and animals with common characteristics gather due to the similar climates. If I were an ecologist, and i will be determining whether an entire river and lake biome is being threatened by human activity, the indicator species that i might look for are the ones that have been introduced into the biome.