In ruminants bacterial action occurs in
(a) Reticulum
(b) Omasum
(c) Abomasum
(d) Rumen

Options

A. Reticulum
B. Omasum
C. Abomasum
D. Rumen

Answer

To solve the question "In ruminants bacterial action occurs in," we need to analyze the four options provided, which are parts of the ruminant stomach.

### Step-by-Step Solution:

1. **Understand the Structure of Ruminant Stomach**:
- Ruminants have a specialized stomach divided into four chambers: Rumen, Reticulum, Omasum, and Abomasum.

2. **Identify the Function of Each Chamber**:
- **Rumen**: This is the largest chamber where microbial fermentation occurs. It is primarily responsible for breaking down fibrous plant material through the action of bacteria.
- **Reticulum**: This chamber is involved in the temporary storage of food and works closely with the rumen but does not primarily carry out bacterial action.
- **Omasum**: This chamber is mainly involved in the absorption of water and nutrients from the digested food.
- **Abomasum**: This is the true stomach of ruminants, where enzymatic digestion occurs, similar to the stomach of non-ruminants.

3. **Determine Where Bacterial Action Occurs**:
- The Rumen is the chamber where the majority of bacterial action takes place, facilitating the fermentation and breakdown of food.

4. **Select the Correct Option**:
- Based on the functions of each chamber, the correct answer is (d) Rumen, as this is where significant bacterial action occurs.

### Final Answer:
The correct answer is (d) Rumen.