Peter belonged to his high school yearbook committee a few years ago. he remembers how much fun they had together, the long hours they worked, and what a great yearbook they produced. amazingly, even though they are all now in college, most of the group members still get together to recall old times and catch up. this is evidence that the group was

cohesive            

Explanation:

Group cohesion: The term group cohesion represents the members of a particular group who work together in a positive environment as well as feels positive about their work.

It can cause both, positive consequences or negative consequences that can often lead to alarming results, same as groupthink.

It causes unity in the different members of a group to work together precisely and satisfy the goals, needs, etc.

A groups' cohesion is being impacted by various factors, for example, trust & member similarity.

In the question above, the statement signifies the evidence about the group being cohesive.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.