Which of these molecules structures could be found in a liquid, but not on a carbohydrate, protein, or a nucleic acid? A. a long chain of carbon, oxygen, and nitrogen atoms
B. a long chain made only of carbon and hydrogen atoms
C. a phosphate group joined to a chain of carbon atoms
D. an amino group and a carboxyl group bonded together ​

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism