What are the major features of embryonic development at the By the end of second month of pregnancy?

Explanation

### Step-by-Step Solution:

1. **Heart Development**: By the end of the first month of pregnancy, the heart of the embryo is fully formed. This is a crucial milestone in embryonic development as it marks the beginning of the circulatory system functioning.

2. **Heartbeat Detection**: Along with the heart being formed, the heartbeat can be detected. This is an important indicator of the embryo's viability and health.

3. **Brain Development**: By the end of the second month, the brain and its parts begin to develop. This includes the formation of the basic structures of the brain, which are essential for the nervous system.

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