DNA polymerase is the enzyme that is responsible for adding correct nucleotide pairs to new and growing DNA strands. Mismatched base pair errors will occur if this enzymes is not able to function optimally. There are other system that work DNA polymerase, these are proof reading system and mismatch repair system. Less than optimum function of these system will lead to uncorrected mismatched base pairs.
You drop it barely above the ground
Though there's no question in the statement above I would assume that you are asking about the pH of the water that is acidic. The correct statement would be:
Any liquid that has a pH less than 7 is called acidic, a pH above 7 is basic or alkaline.
The water in the swimming pool has a high acid concentration due to the chlorine which causes the effect of redness in the eyes.
The best answer - dermal tissue.
Dermal tissue in plants forms the first line of defense against physical damage and infection from the outside world.
Dermal tissue covers the outside of the plant, except in woody shrubs and trees, which have bark. The most common cell type in dermal tissue is epidermal cell. Generally, a thin waxy layer called a cuticle covers the epidermal cells and protects them.
Other cells in the dermal tissue are guard cells that surround the stomata, which are openings in the leaves. Gases enter and leave the dermal tissue through the stomata.
C.75 of the cell's mass is water