When wearing a sterile gown and gloves, why should you not fold the arms with the hands in the axilla?

It can be infected or dissolved

Some of her  assignments would be creation of drugs. she is a medical chemist after all so she'd need to have the necessary knowledge to make medicine which can later be sold in a pharmacy 

That is true tge cactus as a structural adaptation to its envirinment has it leaves reduced to spines. but this doesnt mean it cant produce food it produces food because of the presence of chlorophyll in its stem