A Scientist Suspects That the Food in an Ecosystem May

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 hair produced by humans living in the ecosystem
C) the cholesterol in the cell membranes of organisms living in the ecosystem
D) the cell walls of plants growing in the ecosystem