Potassium, 4 shells, 1 valence electron
It depends on the concentration of nerve receptors in different areas of the skin.
AATTCGCGATTAGCATGA
The complementary strand it what matches to the original. T means the complementary letter will be A (and vise versa), C means the complementary letter will be G (and vise versa).
Hope this helps
B. The water is likely contaminated with high levels of pollution or waste