In classical conditioning, the response is the learned reaction to a previously neutral stimulus.

conditioned response

Explanation:

The conditioned response, in classical conditioning, is the learned reaction that is elicited by an organism to a previously neutral stimulus, which is now a conditioned stimulus.

In the experiment of Pavlov, where the dog was taught to salivate by presenting food and the sound of the bell at the same time, the dog learns to salivate at the sound of bell alone even without food. This response of the dog is termed a conditioned response to a conditioned stimulus (sound of bell).

it is very expensive

explanation:

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.