Ultra Violet rays or UV's cause the skin to burn in the sun.
Having friends that are sexually active and prior sexual activity and dating older people
Answer: A. Medical errors
Explanation:
The research states that medical error comes in next right after deaths caused by heart diseases and cancers (the later two causing at least 250,000 deaths every year).
Adaptive immunity can be acquired during either 'naturally' (by infection) or 'artificially' (through deliberate actions such as vaccination). Adaptive immunity can also be classified as 'active' or 'passive'