Eric wants to find out the most popular after-school activity among high school seniors at his school. what is the population in eric's survey

I believe the answer is: all high school seniors at Eric's school

In survey, population refers to the group of subjects that can be used as a source to collect the data for the survey.
From the description above, eric wants to find out the most popular after-school activity among high school seniors.
This means that all high school seniors' opinion could be used as the data for this question.

Read your textbook to answer that question

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.