Basic principles of embryonic development were stated by

Options

A. von Baer
B. Haeckel
C. Darwin
D. Weismann

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about who stated the basic principles of embryonic development. We have four options: Von Baer, Haeckel, Darwin, and Wiesman.

2. **Identifying Basic Principles of Embryonic Development**: The basic principles of embryonic development refer to the processes that occur after fertilization, leading to the formation of an embryo from a zygote.

3. **Researching the Contributors**:
- **Von Baer**: In 1828, he formulated the basic principles of embryonic development. He is known for his work on the development of embryos and is credited with the idea that the development of an embryo follows a specific sequence.
- **Haeckel**: Ernst Haeckel was a German zoologist known for his opposition to Darwin's theory and for his own theories on evolution, but he did not establish the principles of embryonic development.
- **Darwin**: Charles Darwin is famous for his theory of natural selection and evolution, but he did not specifically address embryonic development principles.
- **Wiesman**: August Weismann proposed the germplasm theory, which discusses the role of germ cells in inheritance but does not focus on embryonic development principles.

4. **Conclusion**: Based on the information gathered, the correct answer to the question is **Von Baer**, as he was the one who stated the basic principles of embryonic development.

**Final Answer**: The basic principles of embryonic development were stated by **Von Baer**.

---