Biology

The correct answer is: B.Second messengers.

Explanation:

In a signal transduction pathway, the molecules mass-produced by enzymes (such as cAMP, calcium ions, or IP3) are called second messengers. These molecules act to amplify and propagate the signal inside the cell after the first messenger (the ligand) binds to the receptor on the cell surface. Second messengers help relay the signal from the receptor to other proteins inside the cell, triggering various cellular responses.

Here’s why the other options are incorrect:

Click "Show Answer" to reveal the answer and analysis