Which one of the following does not digest milk with rennim ?

Options

A. Man
B. Forg
C. Rabbit
D. A calf

Answer

To solve the question "Which one of the following does not digest milk with rennin?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Function of Rennin**: Rennin, also known as chymosin, is an enzyme that curdles milk. It is primarily found in the stomachs of mammals and is crucial for the digestion of milk in young mammals.

2. **Identify the Options**: The options given are:
- a. Man
- b. Frog
- c. Rabbit
- d. A calf

3. **Classify the Organisms**:
- **Man**: A mammal that can digest milk using rennin.
- **Frog**: An amphibian that does not produce rennin and therefore cannot digest milk in this way.
- **Rabbit**: A mammal that can digest milk using rennin.
- **Calf**: A young cow, which is also a mammal and can digest milk using rennin.

4. **Determine the Answer**: Since rennin is characteristic of mammals, we can conclude that the only organism in the options that does not belong to the mammal category is the frog. Therefore, the correct answer is:
- **b. Frog**

### Final Answer:
The organism that does not digest milk with rennin is **b. Frog**.