EVERYDAY SCIENCE

Detailed explanation-1: -blastula, hollow sphere of cells, or blastomeres, produced during the development of an embryo by repeated cleavage of a fertilized egg. The cells of the blastula form an epithelial (covering) layer, called the blastoderm, enclosing a fluid-filled cavity, the blastocoel .

Detailed explanation-2: -A blastocyst is a hollow ball of cells. The cells form two layers. The inner layer is about three to four cells thick and the outer layer is about one cell thick. The cells in a blastocyst divide rapidly.

Detailed explanation-3: -The blastula is a hollow sphere of cells, referred to as blastomeres, surrounding an inner fluid-filled cavity called the blastocoel formed during an early stage of embryonic development in animals.

Detailed explanation-4: -Each cell within the blastula is called a blastomere. Figure 1 (a) During cleavage, the zygote rapidly divides into multiple cells without increasing in size. (b) The cells rearrange themselves to form a hollow ball with a fluid-filled or yolk-filled cavity called the blastula.

Detailed explanation-5: -blastula-Stage of embryonic development of animals near the end of cleavage but before gastrulation. In animals where cleavage (cell division) involves the whole egg, the blastula usually consists of a hollow ball of cells.