Mention one significant difference between morula and blastula.

Explanation

### Step-by-Step Solution:

1. **Definition of Morula**: The morula is an early stage of embryonic development that occurs after several rounds of cell division (mitosis) of the zygote. It is characterized by a solid ball of cells.

2. **Cell Count in Morula**: The morula specifically consists of 16 cells. This stage is reached after the zygote undergoes multiple divisions, leading to the formation of a compact mass of cells.

3. **Definition of Blastula**: The blastula is a later stage of embryonic development that follows the morula. It is characterized by the formation of a hollow structure.

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