The command can be used to view the contents of a record when it is anticipated that the record will need to be modified. It places a shared lock on the record(s) to be changed and prevents any other user from acquiring a lock on the same record(s).

there is an explationation of this on a site called crash   course world history 1

answer; i believe that the correct answer is ( rivers);

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.