The answer is most likely A) cutting down certain trees while leaving other standing.
Feedback mechanism
Feedback mechanism refer to a condition where
every parts of the system is affecting each other, creating one
cause-and -effect notion within the system. Feedback mechanism divided
into 2, positive feedback mechanism and negative feedback mechanism
The answer is (d.) Some scientists believe that prions, tiny proteins much smaller than a cell, that can replicate themselves maybe living organisms.
Prions are like viruses, they are not alive making statement B to be true. Prions lack the ability to grow and reproduce. they are dependent to the living cells to replicate. Statement A is absolutely correct while Statement C is somehow wrong. According to scientists, the accurate count of cells in a human is 37.2 Trillion.