Suppose a group of bobcats that normally live and hunt in the tops of mountains, start hunting prey at the base of the mountain and move into the valley below. which of the following will most likely happen to the prey in the valley? a. their numbers will soon increase. b. their numbers will soon decrease. c. they will move to the tops of the mountains. d. they will remain unchanged.

The right option is; b. Their numbers will soon decrease.  

When the group of bobcats begins to hunt prey at the base of the mountain and move into the valley below, the numbers of the prey in the valley will soon be reduced. The group of bobcats are known as predators. Predators are animals that hunt and kill other animals (their prey) primarily for food.  The activities of predators negatively influence the population of preys in a habitat. When predators hunt and kill other organisms in a habitat, the population of the organisms (prey) will be reduced.

substitution is the answer in this case

not only is it colder, it also becomes darker, less salty, and more dense.