Question

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

Answer 1

The correct developmental order from a zygote to an embryo is cleavage, morula, blastocyst, and gastrula, which involves cell division and restructuring into layers.

Step-by-step explanation:

The correct sequence of development from a zygote to an embryo is as follows: cleavage, morula, blastocyst, gastrula. Initially, the zygote undergoes rapid cell division known as cleavage, forming smaller cells called blastomeres. This process leads to the formation of a morula, which is a solid ball of cells.

Following this, the structure develops into a blastocyst, which has a distinct inner cell mass and is surrounded by an outer layer of cells.

Finally, gastrulation occurs, where the blastocyst reorganizes into a gastrula with different layers that will develop into various tissues and organs of the embryo.

Answer 2

Cleavage, morula, blastocyst, gastrula

Step-by-step 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.