About how many neurons are in the typical human brain?

According to the textbook, what three things do theories do?

tell researchers how to ask questions, give definitive answers to problems give guidance on moral questions, generate discoveries, give solutions to problems produce hypotheses, generate discoveries, offer practical guidance offer practical guidance, concretely explain all aspects of development, produce hypotheses

By pairing the ringing of a bell with the presentation of meat, Pavlov trained dogs to salivate to the sound of a bell even when no meat was presented. In this experiment, the presentation of the meat was the _______

a. unconditioned stimulus b. unconditioned response c. conditioned stimulus d. conditioned response