Which of the following statements is related to karl Ernst von Baer?

Options

A. Embryos never pass through the adult stages of other animals.
B. comparative anatomy shows differences among organisms of today and those that existed years ago.
C. Certain features during embryonic stages are common to all vertebrates that are absent in adult.
D. Ontogeny repeats phylogeny.

Answer

To answer the question "Which of the following statements is related to Karl Ernst von Baer?", we will analyze the contributions of Karl Ernst von Baer to embryology and evolution.

### Step-by-Step Solution:

1. **Understanding Karl Ernst von Baer**:
- Karl Ernst von Baer was an Estonian biologist known for his work in embryology. He is particularly recognized for his contributions to the understanding of the development of embryos in animals.

2. **Key Contributions**:
- He discovered the mammalian ovum (egg), which was a significant finding in reproductive biology.
- Von Baer proposed that the development of embryos does not follow a linear progression. Instead, he suggested that embryos of different species start from a few basic forms that are common to all vertebrates.

3. **Embryonic Development**:
- According to von Baer, while embryos of different animals may start similarly, they diverge as they develop. This means that the initial stages of embryonic development show similarities, but as development progresses, the embryos become more distinct and do not resemble the adult forms of other species.

4. **Analyzing the Statements**:
- One of the key statements related to von Baer is that "embryos never pass through the adult stage of other animals." This aligns with his theory that while embryos may start from a common form, they do not develop into the adult forms of other species.

5. **Conclusion**:
- Based on von Baer's findings, the correct statement related to him is that embryos never pass through the adult stage of other animals. This statement reflects his belief in the uniqueness of embryonic development across different species.

### Final Answer:
The statement related to Karl Ernst von Baer is: **"Embryos never pass through the adult stage of other animals."**

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