A) act independently of each other.
B) are a focus in pest-control research.
C) utilize cell-surface receptors only.
D) are active independently of environmental cues.
E) are not relevant to the study of steroid hormones.

A) an increase in A always produces an increase in X.
B) an increase in X always produces a decrease in A.
C) a decrease in A always produces an increase in X.
D) a decrease in X always causes a decrease in A.
E) it is impossible to predict how A and X affect each other.

A) different target cells have different sets of genes.
B) each cell converts that hormone to a different metabolite.
C) a target cell's response is determined by the components of its signal transduction pathways.
D) the circulatory system regulates responses to hormones by routing the hormones to specific targets.
E) the hormone is chemically altered in different ways as it travels through the circulatory system.