Answer:
Most likely a fungal infection, Onychomycosis (fungal infection of the nail)
Explanation:
The symptoms of Onychomycosis are discoloration, brittleness or thickening.
<span>Air pollution badly affects the health of an individual. Polluted air leads to viral diseases. so the answer is environmental </span><span />
A multiple perspective approach helps historians reconstruct a record of a society.
