17. Protists can be helpful to other organisms by...

c-reactive protein (crp) is an acute phase protein belonging to pentraxin family of proteins, whose levels increases 1000-fold or more in concentration in blood during the occurrence of an injury, inflammation or tissue death.

enzyme speed up the reactions

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