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

Question

Quizplus · Accepted Answer

Hair is made of keratin, a protein, and proteins contain nitrogen. If radioactive nitrogen is present in the ecosystem, it would be incorporated into the proteins, including those in human hair.

A Scientist Suspects That the Food in an Ecosystem May