Which example involves a cell membrane receiving and sending messages? a. the cell membrane prevents glucose from entering a cell. b. cells of an organism tell each other when predators are near. c. a transport protein allows a large molecule to enter a cell. d. an enzyme acts as a catalyst for a reaction on a cell membrane.

The right answer is B.

The membrane plays an important role in communication (signal transmission) within the body.

In the nervous system, neurons communicate with each other and with effector cells (such as muscle cells) through specialized contacts called synapses. Like muscle cells, neurons are cells capable of generating fast electrical pulses on their membrane surface. These electrical pulses are used to transmit signals along the membranes of nerve (and muscle) cells.