Most of our cells are surrounded by:

Options

A. blood
B. interstitial fluid
C. pure water
D. air

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Question**: The question asks what surrounds most of our cells. We need to identify the correct option from the choices provided.

2. **Basic Unit of Life**: All living organisms are made up of cells, which are the basic structural and functional units. Cells perform various functions necessary for life.

3. **Components of a Cell**: Each cell contains cytoplasm and is surrounded by a membrane. Within the cytoplasm, there are organelles such as mitochondria, endoplasmic reticulum, and ribosomes.

4. **Surrounding Fluid**: Around the cells, there is a fluid that is present in a very thin layer. This fluid is known as **interstitial fluid** (or tissue fluid), which exists between the cells and blood vessels.

5. **Nutrient Transport**: The interstitial fluid contains nutrients and facilitates the exchange of materials between blood and cells.

6. **Evaluating Options**:
- **Blood**: While blood is essential for transporting substances, it does not directly surround the cells. Thus, this option is incorrect.
- **Pure Water**: Although cells contain a significant amount of water, they are not surrounded by pure water. This option is also incorrect.
- **Air**: Air does not surround cells directly; it interacts with blood and is involved in gas exchange. Therefore, this option is incorrect as well.
- **Interstitial Fluid**: This is the correct answer as it is the fluid that surrounds most cells in the body.

7. **Conclusion**: The correct answer is **Interstitial Fluid**.