B because we go out in public and touch stuff
A n environmental stressor could be;
the weather, too hot, say a heatwave, which can cause heat stroke, dehydration etc, or too cold, where vulnerable people may freeze to death, or develop frost bite etc.
So, some characteristic part of where we live which may, under certain conditions cause difficulty for us or some other living being.
B it may be due to extensive radiation therapy as it can increase the risk of this type of cancer
BIODEGRADABLE. Is what they are called
