The main purpose of mitosis is to certify that daughter cells must get the same genetic info, which is transferred in replicated chromosomes. In order to fulfill this objective, cells employ a microtubule-based molecular machine named a spindle. Chromosomes attach to the spindle through kinetochores and separate macromolecular associations that exist at the chromosome centromere. On every single chromosome, two kinetochores must assign to the contrasting spindle poles. Microtubules shrink and grow until steadied and captured by a kinetochore. In diploid human cells, mitosis takes fewer than 30 minutes. This inconsistency suggests that other mechanisms arrange chromosomes to the high-density microtubules areas and help mitotic spindle association by guiding microtubules' growth toward kinetochores, in mitosis, spindle forms in 3-D space. The spatial departure of replicated centrosomes determines the orientation and length of the spindle. This separation might take place during prometaphase or prophase.
The answer is (b.) ecosystem. An ecosystem is all living organism in an area functioning together with nonliving factors of the environment. An Ecosystem is a community of the living organism that includes the producers, the consumers, and the decomposers.