Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because
a. only target cells retain the appropriate dna segments.
b. intracellular receptors are present only in target cells.
c. only target cells have enzymes that break down aldosterone.
d. only in target cells is aldosterone able to initiate the phosphorylation cascade that turns genes on.

The correct answer is option b.

Explanation:

Aldosterone is a mineralocorticoid, that is, a steroidal hormone that plays important role in regulating blood pressure as well as the levels of sodium and potassium in the plasma.

It is released from adrenal gland. Being steroidal in nature, it is capable of bypassing plasma membrane easily.

However, its receptors are present inside the cell, that is, in cytoplasm.

These receptors are expressed or present only in the target cells due to which this hormone produces its effects only in the target cells.

Once bound to intracellular receptor, the cell signalling results in alterations in gene expression which produces the desired effects.

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.

currents is the correct answer.