What steroid acts as the molecular building block of the human steroid hormones?

The correct answer is cholesterol.

Explanation:

Steroid hormones refer to the fat-soluble molecules produced from cholesterol. Of these, the three prime groups of sex hormones are androgens, estrogens, and progesterone. All these are produced in both males and females, however, in different concentrations.  

The steroid passes through the nucleus of the cell, and combines with specific receptors and genes and stimulate the cell to produce proteins.  

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.