A) Write down three letters that show arteries. b) Write down one letter that shows capillaries.
c) Write down two letters that show veins.
d) Write down three letters that show vessels containing deoxygenated blood.

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