The answer is
dog food. Classical conditioning<span> refers to
learning process in which a potent stimulus is harmonized with a former neutral
stimulus. The neutral stimulus is also known as the conditioned stimulus (in
this question, the dog food). It first brings out no response then when
something is associated with the scream of the mother; it became now the conditioned
stimulus.</span>
Two nations that most immigrants came from during the mid-1800s include Germany and Ireland.
:)
The correct answer among the choices given is option B. The purpose of an expectorant is to liquefy mucous. An expectorant is a drug that aids in the clearance of mucus in the respiratory system. It thins out mucus so it can be expelled from the body easier.
