Biology

The correct answer is: C.Ligand.

Explanation:

In cell communication, a ligand is the signaling molecule that binds to a receptor on the surface of a cell or inside the cell. This binding typically triggers a cascade of events inside the cell, leading to a specific cellular response.

Here’s why the other options are incorrect:

A.Carbohydrate chain: Carbohydrate chains are involved in cell recognition and...