Lowest level of organistation among eumetazoans is

Options

A. tissue level
B. cellular level
C. organ - system level
D. tissue -organ level

Answer

To determine the lowest level of organization among eumetazoans, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Eumetazoans**:
- Eumetazoans are multicellular organisms that are distinguished from simpler forms of life, such as Porifera (sponges) and Placozoa. They include both vertebrates and invertebrates.

2. **Identify Levels of Organization**:
- The levels of biological organization include cellular level, tissue level, organ level, organ system level, and organism level.

3. **Analyze the Options**:
- The options given are:
- Tissue level
- Cellular level
- Organ system level
- Tissue-organ level

4. **Eliminate Incorrect Options**:
- Since eumetazoans are multicellular, they cannot be at the cellular level of organization. Therefore, the cellular level is not the correct answer.
- The organ system level and tissue-organ level are higher levels of organization than tissue level.

5. **Determine the Correct Answer**:
- The lowest level of organization among eumetazoans is the **tissue level**. This is where cells are organized into tissues that perform specific functions.

### Final Answer:
The lowest level of organization among eumetazoans is the **tissue level**.

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