The human body has an organ A which acts as a pump. The pump A pumps a liquid B into the whole body continuously. The liquid B supplies the useful substances C and D to all the body cells and removes a waste E from the body cells.
Name the useful substances C.

Answer

To answer the question, we need to identify the useful substances that are supplied by the liquid pumped by the heart in the human body. Let's break it down step by step:

### Step-by-Step Solution:

1. **Identify the Organ (A)**: The question states that there is an organ (A) that acts as a pump. In the human body, this organ is the heart.

2. **Identify the Liquid (B)**: The liquid that is being pumped throughout the body by the heart is blood.

3. **Understand the Function of Blood**: Blood serves multiple functions, including transporting nutrients and oxygen to the cells and removing waste products.

4. **Identify Useful Substances (C and D)**:
- The useful substances that blood supplies to the body cells include:
- **C**: Digested food, which refers to nutrients (like glucose, amino acids, vitamins, and minerals).
- **D**: Oxygen, which is essential for cellular respiration.

5. **Identify the Waste (E)**: The waste that is removed from the body cells is carbon dioxide, which is a byproduct of cellular respiration.

### Final Answer:
The useful substance C is **digested food (nutrients)**.

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