chemically, what is an important factor that enables enzymes to separate the strands of dna without breaking them?

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

b) the inside picture would look at a very high temperature in a very low ph