Question

lipid soluble signaling molecules, such as testosterone, cross the membrane of all cells, but effect only target cells because ...

only target cells retain the appropriate dna segments.

intracellular receptors are present only in target cells.

most cells lack the y chromosome required.

only target cells possesses the cytosolic enzymes that transduce the testosterone.

only in target cells is testosterone able to initiate a phosphorylation cascade.

Explanation:

Lipid - soluble signaling molecules like testosterone can cross cell membranes freely. Their effect is specific to target cells because only target cells have the appropriate intracellular receptors. These receptors bind to the signaling molecule and initiate a cellular response. DNA segments are the same in most somatic cells in an organism, so it's not about DNA segments. Testosterone action doesn't depend on the Y - chromosome in this context. Cytosolic enzymes for transduction and initiation of phosphorylation cascade are not the main determining factors for target - cell specificity in this case.

Answer:

B. intracellular receptors are present only in target cells.