Which of the following is the correct sequence of development from zygote to embryo?
cleavage, gastrula, morula, blastocyst
blastocyst, cleavage, gastrula, morula
cleavage, blastocyst, morula, gastrula
cleavage, morula, blastocyst, gastrula

Cleavage, morula, blastocyst, gastrula

Explanation:

The zygote is formed after fertilization of sperm and ovum. Then the zygote undergoes a repeated cell division to form a number of cells. These tiny cells formed by mitotic cell division but present inside the zygote. It forms 2 cells then 2 cells, then 8 cells and so on. After forming the number of cells the zygote has a number of tiny cells. This stage is called morula and the tiny cells are called morulae. Then these cells migrate towards the periphery of the morula and creating a central space called blastocoel. This hollow ball structure is known as the blastocyst. After this blastocyst stage, the cells migrate to form 3 layers such as endoderm, mesoderm, ectoderm. From this layer different organs are formed. This 3 layered stage is known as gastrula. Thus the zygote development starts from cleavage, morula, blastula, and gastrula.

cancer   is   essentially   uncontrolled   mitosis   of specialized cells