In experiments that compare all-mental practice to all-physical practice and no practice conditions, results typically show that participants in the all-mental practice condition learn the skill:

B. not as well as those in the all-physical practice condition but better than those in the no practice condition.

Explanation:

The reason behind this answer that the all-physical practice condition participants learn skills better than all-mental practice condition who learn better than the no practice condition participant is because of the ability to create a perspective by handling the objects involved in the tasks. Of course here, the type of the task also matters but the hands on approach helps the learner in most cases. On the other hand, the all-mental practice condition participants might do well in tasks related to mental capacity only but in general does not perform better than all-physical practice condition.

A. isolationism

Explanation:

When the World War I broke out, the United States didn't planned to get involved in it. Initially, the United States considered this war to have anything to do with them, so they adopted a policy of isolationism. The reason for adopting isolationist policy was to protect its social, economic, and political interest. This quickly changed though, and the United States got involved in the second half of the war, so the isolationism was very short-lasting.