Final answer:
Telomeres shorten after cellular division because most somatic cells lack telomerase, which leads to the progressive loss of the protective chromosome ends known as telomeres, signifying cellular aging. the correct answer is B .
Step-by-step explanation:
After cellular division, telomeres get shorter. This is because most somatic cells lack the enzyme telomerase, which normally adds repetitive nucleotide sequences to the ends of chromosomes, thereby preventing or reducing shortening. Each time a cell divides, a small portion of the telomere is lost due to the inability of the DNA replication machinery to completely replicate the ends of linear chromosomes.
As a consequence, with each round of cell division, the telomere length gets progressively smaller. This process is associated with cellular aging and a decline in the ability of cells to divide, known as replicative senescence. Telomere shortening can, therefore, be considered a marker of cellular aging. Outside of the somatic cells context, certain cells, like stem cells and germ cells, do produce telomerase, allowing them to maintain telomere length and thereby possess a greater capacity for division.