The cavity of blastocyst is called ...............

Explanation

The cavity of the blastocyst is called the **blastocoel**.

### Step-by-Step Solution:

1. **Understanding the Blastocyst**: The blastocyst is a structure formed in the early stages of embryonic development. It develops from the zygote through a series of mitotic divisions known as cleavage.

2. **Formation of the Blastula**: The term "blastula" is often used interchangeably with "blastocyst." The blastula is characterized by a hollow structure formed during the cleavage stage.

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