Digestion in Hydra occurs

Options

A. Intracellularly in gastrodermal cells only
B. Extracellularly in gastro-vascular cavity followed by intracellular digestion within gastrodermal cells
C. Extreacellularly in gastrovascular cavity only
D. Intracellular in gastrodermal cell followed by extracellular digestion in coelenteron

Answer

### Step-by-Step Solution:

1. **Understanding Hydra's Classification**:
- Hydra belongs to the class Hydrozoa. This classification is important as it helps us understand the biological characteristics and processes of Hydra.

**Hint**: Remember that classification helps in understanding the organism's biology.

2. **Phases of Digestion in Hydra**:
- Digestion in Hydra occurs in two distinct phases: extracellular digestion and intracellular digestion.

**Hint**: Think of digestion as a two-step process in Hydra.

3. **Extracellular Digestion**:
- The first phase is extracellular digestion, which takes place in the gastrovascular cavity. Here, preliminary digestion occurs outside the cells of the endodermis.

**Hint**: Extracellular digestion happens outside the cells, in a specialized cavity.

4. **Intracellular Digestion**:
- The second phase is intracellular digestion, which occurs inside the gastrodermal cells. In this phase, the digested food is absorbed by the cells.

**Hint**: Intracellular digestion involves the absorption of nutrients by the cells.

5. **Evaluating the Options**:
- Option 1 states that digestion occurs intracellularly in gastrodermal cells only, which is incorrect since it omits the extracellular phase.
- Option 2 states that digestion occurs extracellularly in the gastrovascular cavity followed by intracellular digestion within gastrodermal cells. This is the correct answer.
- Option 3 states that digestion occurs extracellularly in the gastrovascular cavity only, which is incomplete.
- Option 4 states that digestion occurs intracellularly in gastrodermal cells followed by extracellular digestion in cylindrons, which is also incorrect.

**Hint**: Carefully analyze each option based on the two phases of digestion discussed.

6. **Conclusion**:
- The correct answer is Option 2: Digestion in Hydra occurs extracellularly in the gastrovascular cavity followed by intracellular digestion within gastrodermal cells.

**Hint**: Always summarize your findings to reinforce the correct answer.