Why do sponges not have blood?

Explanation

### Step-by-Step Solution:

1. **Understanding Sponges**: Sponges are simple aquatic animals that belong to the phylum Porifera. They are among the most primitive multicellular organisms.

2. **Lack of Circulatory System**: Unlike more complex animals, sponges do not possess a circulatory system. This means they do not have blood or any specialized vessels to transport nutrients and waste.

3. **Role of Water**: Sponges rely on water for their physiological processes. They have a unique system of pores and channels that allow water to flow through their bodies.

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