Question

there is evidence that there is a limit to the number of times a cell can divide before it stops dividing. the structures that probably cause this are called ________.
answer options: telomeres, m - phase promoting factor, activator genes, growth factors, i dont know yet

Explanation:

Telomeres are repetitive nucleotide sequences at the ends of chromosomes. With each cell division, telomeres shorten, and when they become too short, the cell stops dividing. M - phase promoting factor is related to cell cycle progression (specifically mitosis), activator genes are involved in gene expression activation, and growth factors stimulate cell growth and division. So the structure limiting cell division number is telomeres.

Answer:

telomeres (the option with "telomeres" text, the first circular option in the answer choices)