Most favourite food of hydra is

Options

A. bacteria
B. water fleas
C. tadpoles of frog
D. fishes

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: The question asks about the favorite food of Hydra, which is a member of the Phylum Cnidaria.

2. **Understand the Feeding Mechanism**: Hydra is known for its predatory nature. It uses a combination of extracellular and intracellular digestion. This means it first breaks down food outside its body using enzymes and then absorbs the nutrients.

3. **Determine the Type of Food**: As a heterotroph, Hydra does not produce its own food but instead consumes other organisms.

4. **List Potential Food Sources**: The transcript mentions several potential food sources for Hydra, including insects, larvae, worms, small crustaceans, and specifically water fleas.

5. **Choose the Correct Answer**: Among the options provided, water fleas are highlighted as the most favored food for Hydra due to their small size, which makes them suitable for Hydra to capture and consume.

6. **Conclusion**: Therefore, the most favorite food of Hydra is water fleas.