11) the statement "the quantity demanded of a product varies inversely with its price" is a definition of

The quantity demanded of a product varies inversely with its price is the definition of the law of demand. 

In other words, if the product increases that means that the demand is going to increase as well. Or, if the price of the product decreases then the demand on the produce will increase. 

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.