The four reasons are
1) There is an over population.
2) There is a genetic variation in certain offspring that is helpful to survival.
3) The species struggle for survival.
4) The ones that lives will reproduce and pass on their genetic variation.
I hope that's help:0
Answer: the answer is (d)
Explanation:
The difference between pH 3 and pH 4 is a 10 fold difference in the concentration of H+
