The concept that organiser is essential for embryonic development was given by or For the ‘Theory of organiser’, Nobel prize was given to

Options

A. J. Axelrod
B. C. Landsteiner
C. H. Spemann
D. I.P. Pavlov 9

Explanation

To answer the question regarding the concept of the organizer in embryonic development and the Nobel Prize awarded for it, we can follow these steps:

### Step 1: Understanding the Concept of Organizer
The "organizer" refers to a group of cells that play a crucial role in the embryonic development of an organism. It was first studied in detail by scientists who observed how certain cells could influence the development of surrounding tissues.

**Hint:** Think about the role of specific cells in guiding the development of an embryo.

### Step 2: Identifying the Scientists Involved
The theory of the organizer was primarily developed by two scientists: Hans Spemann and his collaborator, who is often recognized alongside him. This concept is known as the "Spemann-Mangold organizer."

**Hint:** Recall the names associated with the theory of organizer and their contributions to developmental biology.

### Step 3: Nobel Prize Recognition
Hans Spemann was awarded the Nobel Prize for his work related to the organizer concept. His experiments demonstrated how certain cells could direct the development of other cells, which is fundamental in embryology.

**Hint:** Remember that the Nobel Prize is awarded for significant contributions to science, and in this case, it was for work in embryonic development.

### Step 4: Eliminating Other Options
The other names mentioned (J. Axelrod, C. Landsteiner, I. P. Paolo) are associated with different scientific contributions. For example, Carl Landsteiner is known for discovering blood groups, not for the organizer theory.

**Hint:** Consider the contributions of each scientist listed in the options to determine who is relevant to the organizer theory.

### Step 5: Conclusion
Based on the information gathered, the correct answer to the question is Hans Spemann, who was awarded the Nobel Prize for his work on the concept of the organizer in embryonic development.

**Final Answer:** Hans Spemann (Option C).