Professor thurstone investigates whether a teacher's negative perceptions of some students can affect the students' test scores. professor thurstone is most likely a psychologist.

Social (psychologist).

Explanation:

Given that Professor Thurstone is investigating a teacher's negative perceptions influence in the student's tests, he is most likely a social psychologist. This type of psychology studies how people's (not individuals per se) thoughts, feelings and behaviors are influenced by the presence of others. In this case, his group of individuals would be the students, and the influence he is studying is that of the teacher that causes negative perceptions in his group of study.

d. the polar jet stream   lies between the polar easterlies and trade winds should be your answer

answer; observing;