What is the function of the telomere?
a. to act as the site for the start of replication
b. to keep plasmid dna circular
c. to hold together sister chromatids
d. to protect the end of a dna molecule

d. to protect the end of a DNA molecule

Explanation:

Telomeres are like the protective shields of our cells' DNA.

Its name, of Greek origin, literally means "final part", and the telomeres are that: the ends of the chromosomes, something similar to the plastic tips of the shoelaces.

But they are very repetitive and non-coding parts of DNA: their main function is to protect the genetic material that carries the rest of the chromosome.

As our cells divide to multiply and to regenerate the tissues and organs of our body the telomere length is reduced, and so over time they become shorter.

When the telomeres finally remain so small that they can no longer protect the DNA, the cells stop reproducing: they reach a state of old age or old age.

Therefore, telomere length is considered a key "biomarker of aging" at the molecular level, although it is not the only one, and in recent years it has attracted the attention of numerous investigations.

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.

b. the carbon cycle ensures living things have a source of hydrogen