EVERYDAY SCIENCE

Detailed explanation-1: -The development of multi-cellular organisms begins from a single-celled zygote, which undergoes rapid cell division to form the blastula. The rapid, multiple rounds of cell division are termed cleavage.

Detailed explanation-2: -Cleavage. After fertilization, the development of a multicellular organism proceeds by a process called cleavage, a series of mitotic divisions whereby the enormous volume of egg cytoplasm is divided into numerous smaller, nucleated cells. These cleavage-stage cells are called blastomeres.

Detailed explanation-3: -The correct option is B cleavage. The zygote which is formed after fertilisation is a single cell which divides mitotically to produce multiple cells (blastomeres). The mitotic divisions of the zygote are called as cleavage.

Detailed explanation-4: -The zygote is a single diploid cell, which will ultimately multiply through mitotic division to form a multicellular embryo. This mitotic division does not result in any significant growth and the multicellular cluster that is formed is the same size as the zygote. This cell division process is referred to as cleavage.

Detailed explanation-5: -Cleavage is the repeated mitotic division of zygote to form a solid ball of cells called morula which later changes into a hollow ball of cells called blastula. Cleavage of human zygote occurs within the fallopian tube. It is holoblastic, i.e., it divides the zygote completely into daughter cells or blastomeres.