A. correctly identifies people as having the disease when, in fact, they do. b. may cause unnecessary stress, anxiety, and treatment. c. may cause a false sense of security. d. the preferred situation to be in.

Clean air provides nitrogen

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.