Biology

The correct answer is A.pump transport.

This type of membrane protein is known as a co-transporter or antiporter. In antiporters, one substance is transported in one direction, while another substance is transported in the opposite direction, often using energy (such as ATP). An example of this is the sodium-potassium pump (Na+/K+ ATPase), which actively transports sodium ions (Na⁺) out of the cell and potassium ions (K⁺) into the cell.

Here’s a breakdown of the other terms:

B.Bulk transport refers to the movement ...