OBJECTIVE LIFE SCIENCE
DEVELOPMENTAL BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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infolding of the blastula leading to gastrulation
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cells migrating to the outside to form a hollow ball of cells-the blastula.
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maternal/cytoplasmic determinants differentiating cells
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axis induction by the sperm entry point.
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Detailed explanation-1: -The typical blastula is a ball of cells. The next stage in embryonic development is the formation of the body plan. The cells in the blastula rearrange themselves spatially to form three layers of cells in a process known as gastrulation.
Detailed explanation-2: -This process is called gastrulation. During gastrulation, the blastula folds in on itself and cells migrate to form the three layers of cells (Figure 13.10) in a structure, the gastrula, with a hollow space that will become the digestive tract.
Detailed explanation-3: -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.