Answer: In his experiment, Pavlov used a metronome as his neutral stimulus. By itself the metronome did not elicit a response from the dogs. Next, <u>Pavlov began the conditioning procedure, whereby the clicking metronome was introduced just before he gave food to his dogs.</u>
Answer is A.
:)
By several tries and studies
<span>A. If one essential nutrient within an ecosystem runs out, primary productivity will be limited.
A specific nutrient is need for every organism in the ecosystem. If this particular nutrient is diminished within the ecosystem then cellular processes will decreases and a great number of specie will die. </span>
I believe the answer is organic compound
D. A deceased family member
