The developed the process of glass blowing and thus made commonplace

The Romans developed the process of glass blowing and thus made glass containers commonplace. Glassblowing is a technique to form glass. It involves heating glass up to a molten state then blowing and spinning it to form a bubble. Once the bubble is formed, it can be blowing into many different shapes as it is reheated, twirled and blown. A person who does this work is often referred to as a gaffer or glassmith.

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.