How do scientists know how reconstruct a fossil? Each fossil piece fits together perfectly.
Scientists will use the structure of existing animal as a model.
The location of each fragment found provides clues on how the animal looks.
There are labels found in each of the fossil bones.

I think it’s the second one.

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.