In general, how would a 10-year-old child be a more reliable eyewitness regarding the facts of an event than a 40-year-old adult, and vice versa? why?

I believe that a ten-year-old would be a better eyewitness because generally kids are more attentive than adults when they see something they are interested in. A child is more likely to remember important details and then recall them from memory than an adult, whose mind is slowly deteriorating and he may forget relevant details. 

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.