Help me please...multiple choice?

a scientist suspects that the food in an ecosystem may have been contaminated with radioactive nitrogen over a period of months. which of the following substances could be examined for radioactivity to test the hypothesis?

a. the sugars produced during photosynthesis by plants growing in the ecosystem

b. the cholesterol in the cell membranes of organisms living in the ecosystem

c. the hair produced by humans living in the ecosystem

d. the cell walls of plants growing in the ecosystem

e. any of these choices would work well

thanks for your help.

Help me please...multiple choice?

I can tell you that it will not be A because nitrogen is not part of the formula for photosynthesis. I would pick either b or d if I had to make an educated guess.

Help me please...multiple choice?

The only substance in the list of choices that contains nitrogen in significant quantities is the hair of humans. Sugars, cholesterol and cell walls are all composed of carbon, hydrogen and oxygen, and do not contain nitrogen.

So, C is your best answer.

Help me please...multiple choice?

C. The hair.

The thing is, sugar, cholesterol, and cellulose don't contain nitrogen.