Question

Arrange the following in their order of occurrence.
I. Formation of the embryo.
II. Cells arrange themselves into different layers.
III. The zygote undergoes multiple cleavages.
IV. Formation of germ layers.

• A. II, IV, III, I
• B. I, III, IV, II
• C. IV, II, III, I
• D. III, I, II, IV

Answer 1

The correct option is D III, I, II, IV

The male gamete (sperm) and female gamete (egg) fuse to form the zygote. This process is called fertilization. The zygote undergoes multiple cleavages (cell division) to form the embryo. During the formation of an embryo, the cells arrange themselves into different layers. Cells of each layer contribute to the formation of tissue or organs. These layers are known as germ layers. The different germ layers are - ectoderm (outermost layer), mesoderm (middle layer), and endoderm (innermost layer).