Lipid-soluble signaling molecules, such as testosterone, 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) most cells lack the y chromosome required.
d) only target cells possess the cytosolic enzymes that transduce the testosterone.
e) only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.

option B) intracellular receptors are present only in target cells.

Explanation:

The cell membrane or plasma membrane is composed of phospholipids and thus hydrophobic in nature, this allows the lipid soluble signaling molecules to cross the membrane. The cell membrane of all cells consist of phospholipids thus hydrophobicity of each cell membrane allows lipid soluble signaling molecules to pass through the plasma membrane. The testosterone cross the membranes of all cells but affect only target cells because of intracellular recepters that are located in target cell. The binding of signaling molecules to recepter generates a response. Thus, option B is correct.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?