Question

Cleavage differs from mitosis because
(a)In cleavage, there is no growth phase
(b)In cleavage consumption of $O_2$ increases
(c)In cleavage nucleus-cytoplasmic ratio increases
(d)All the above

Answer 1

Hint: The single-cell stage of life called the zygote begins to divide to form multiple cells. During this process, the number of cells is gradually increased but these cells do not get bigger in size.

Complete answer:
Cleavage is the mechanism of cytoplasm division (cytokinesis) within animal cells. In the cleavage nucleus: the cytoplasmic ratio increases. Cleavage is a very quick process and thus the intake of $O_2$ is extremely high. In the cleavage site, the growth process does not occur.
The first few cellular divisions of a zygote (fertilized egg) are called cleavage, in embryology. These early divisions create separate cells called blastomeres. In all blastomeres (cells) the first few cleavages occur simultaneously, but as the number of cells grows, simultaneity is lost, and the blastomeres divide independently. New chromatin is formed between the divisions by the cytoplasmic divisions. The cleavage can be holoblastic (total or whole cleavage) or meroblastic (partial cleavage), depending mostly on the amount of yolk in the egg.
Whereas during mitosis, the nucleus splits into two separate nuclei. In the mitosis nucleus: the cytoplasmic ratio remains the same. Development occurs at interphase. Mitosis occurs in the somatic cells (non-reproductive cells). It slows the synthesis of DNA.

So, the correct answer is ‘All the above’.

Note: Cleavage occurs during the zygote stage where there will be no growth of the cells, and the number of cells will increase. In the case of mitosis, the division occurs to form germ cells as well as replace the worn out and damaged cells.