Which of the following best describes an antibody?

1. Protane the targets and blocks and molecules
2. A molecule that causes the body to react negatively to certain substances
3. A tiny invader, like a virus,
bacterium or parasite
4. A molecule that provides energy to the body

B. A molecule that causes the body to react negativly to certain substances.

Explanation:

Antibody (Ab) also known as immunoglobulin (Ig) is a large Y shaped protein produced by plasma cells. They are used by the body's immune system to neutralize pathogens like harmful bacteria and viruses.

They are secreted by the B cells of the adaptive immune system mostly by differentiated B cells called plasma cells. They are glycoproteins.

the answer to your question is:

c. complementary base-pairing

the food storage products of chrysophytes are oils or the polysaccharide laminarin.   formerly classified as plants, the chrysophytes contain the photosynthetic pigments chlorophyll a and c all but the yellow-green algae also contain the carotenoid pigment fucoxanthin.