Trains have developed over the years as technology has improved. Now, there are electronic trains that do not need conductors to run them. These conductorless electronic trains are beneficial because , but they also have disadvantages such as .

the answer is trees if i'm not mistaken

this is math not biology xd

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