Explain how some heterotrophs could be described as either a primary consumer or a secondary consumer.

Omnivorous animals can be described as a primary consumer or a secondary consumer.

Explanation:

Some heterotrophs can derive their nutrition from plant sources and animal sources both. These organisms are called omnivorous animals. When an omnivorous organism derives its nutrition from plant sources, it serves as a primary consumer. On the other hand, when the same omnivorous organism derives its nutrition from animal sources, it serves as a secondary consumer. Squirrels and rats are examples of such heterotrophs.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

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