Which of these is generally feature of the lipid bilayer in all biological membranes?

answer; ///(b) it is composed of four protein chains and four heme groups;

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