Answer:
The correct option is : b. centrosome
Explanation:
Centrosome is a cell organelle, which acts as the microbule organizing center and also regulates the cell cycle progression in an eukaryotic cell.
During the prophase stage of the cell cycle, the centrosomes are associated with the membrane of the nucleus. The nuclear membrane ruptures during the mitosis and the interaction of the centrosome nucleated microtubules with the chromosomes leads to the formation of the mitotic spindle.
<u>Therefore, mitotic spindles arise from the centrosome.</u>
Elderly people are most at risk
from minor trauma that results in serious spinal cord injury because of
preexisting degenerative vertebral disorders. Males are more prone to spinal
cord injuries than females but not as a result of preexisting disorder. This
may be related to an increased involvement in contact sports or a propensity to
participate in high risk activities. Neither females nor infants are at any
particular risk for spinal cord injuries.
Robert Hooke was the first scientist to discover cell. This discovery was made possible by the use of microscope which he invented. With this microscope, Robert examined a cork and noticed pores which filled the entire volume of the thin slices of cork; he called the pores cells. This discovery was made in January 1653.
