HELP PLZ !!! What is the role of a keystone species? Limiting the abundance of a competitively dominant species
Populating the ecosystem to decrease diversity
Exploiting the key resources in an ecosystem
Competitively dominant to other organisms in the ecosystem

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.