Answer:
Pb has an atomic mass of 82. If an atom of that element has an atomic mass of 80, that atom is known as: an isotope.
Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.
No choice given but this type of research deals with the response to drugs of people according to their genetic make-up. Pharma means drugs and genomics is to do with the genes. The purpose is to suit the drugs to a person's actual genetic make-up so the drugs will be compatible with their genes.
