Which example best represents the ability of carbohydrates to serve as structural components?
a. the muscles of animals are held together by connective tissue.
b. the rigid cell wall of green plants is composed of cellulose.
c. the bones of animals store minerals such as calcium phosphate.
d. the roots of many plants store glycogen produced by the plant.

B, The rigid cell wall of green plants is composed of cellulose.

Explanation:

Cellulose is an organic compound, classified as a carbohydrate, that makes up a tough cell wall surrounding plant cells. It is a polysaccharide with beta 1, 4 d-glucose linkages (very strong bonds) making it very difficult to degrade by hydrolysis and enzymatic action. Through that, cellulose serves an important structural component because it provides roots and stems their rigidity, toughness and protection from microbial degradation.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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