Baby Jacob's mother is more likely to pick him up when he smiles than when he is fussy. As a result, the frequency of Jacob's smiles has increased. This is an example of

Operant conditioning.

Explanation:

Operant conditioning refers to a  learning method that obtains through rewards and punishments to measure change in behavior. By operant conditioning, there is a correlation made between an action and a reason for that behavior. According to this theory, actions followed by positive effects are likely to repeat in future scenarios. As per the question, Jacob associates his smile and his mother's reaction of picking him up and therefore perfect example of operant conditioning.

according to hess's theory, when the magma cooled, it would expand and push the tectonic plates apart. it would push the north and south america plates to the west and eurasia and africa ones to the east. the atlantic ocean would get wider but the coastlines of the masses would stay the same.

harry hammond hess was a geologist and a united states navy officer in the second world war. he is considered to be one of the founding fathers of the theory of plate tectonics. he is known for his theories on sea floor spreading, stating that the movement of the continents was the result of see floor spreading. the continents are attached to the plates and do not move separately. the plates themselves shift and change shape, carrying the continents along.