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.
What are liquid B?

Answer

To answer the question regarding what liquid B is in the human body, we can follow these steps:

### Step 1: Identify the Organ A
The question states that there is an organ A that acts as a pump in the human body. In humans, the heart is the organ that functions as a pump, circulating blood throughout the body.

**Hint:** Think about which organ in the body is responsible for pumping fluids.

### Step 2: Determine Liquid B
Liquid B is the substance that is pumped by organ A (the heart). In the human body, the liquid that is continuously pumped by the heart is blood.

**Hint:** Consider what fluid is circulated by the heart and is essential for transporting substances.

### Step 3: Understand the Function of Liquid B
Liquid B (blood) serves several important functions. It transports useful substances such as nutrients and oxygen to body cells and also carries away waste products.

**Hint:** Reflect on the components of blood and their roles in the body.

### Step 4: Identify Useful Substances C and D
The useful substances that blood supplies to the cells include nutrients (C) such as glucose and oxygen (D). These are essential for cellular respiration and energy production.

**Hint:** Think about what nutrients and gases are vital for the survival of cells.

### Step 5: Identify Waste E
The waste that blood helps to remove from body cells includes nitrogenous waste (E), which is a byproduct of protein metabolism. This waste is typically excreted through the kidneys.

**Hint:** Consider what types of waste products are produced in the body and how they are eliminated.

### Final Answer
Liquid B is **blood**.

### Summary
- Organ A: Heart
- Liquid B: Blood
- Useful substances: Nutrients (C) and Oxygen (D)
- Waste: Nitrogenous waste (E)