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 about which statement is related to Karl Ernst von Baer, we can follow these steps:

### Step 1: Understand von Baer's Law
- Karl Ernst von Baer was a German scientist known for his contributions to embryology. He proposed that during embryonic development (ontogeny), general characteristics of a group appear before specialized characteristics. This means that early embryos of different species show similarities, while later stages reveal more specific traits.

### Step 2: Analyze the Statements
- We need to evaluate the given statements to determine which one aligns with von Baer's principles:
1. **Embryos never pass through the adult stages of other animals.**
2. **Comparative anatomy shows differences among organisms of today and those that existed years ago.**
3. **Certain features during embryonic stages are common to all vertebrates that are absent in the adult.**
4. **The statement of the biogenetic law that Haeckel has given us.**

### Step 3: Evaluate Each Statement
1. **Statement 1**: This aligns with von Baer's law, as it emphasizes that embryos do not resemble the adults of other groups but rather share general characteristics.
2. **Statement 2**: This is incorrect according to von Baer's principles, as comparative anatomy often reveals similarities due to common ancestry.
3. **Statement 3**: While it mentions common features in embryonic stages, it does not accurately reflect the distinction between general and specialized characteristics that von Baer emphasized.
4. **Statement 4**: Although it relates to embryonic development, it is more about Haeckel's biogenetic law rather than von Baer's specific contributions.

### Step 4: Conclusion
- The correct statement related to Karl Ernst von Baer is **Statement 1**: "Embryos never pass through the adult stages of other animals." This reflects his idea that embryos exhibit general traits first, which later differentiate into specialized traits.

### Final Answer
The correct answer is **Statement 1**: "Embryos never pass through the adult stages of other animals."

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