Blood cells retain their normal shape in solution which are

Options

A. hypotonic to blood
B. isotonic to blood
C. hypertonic to blood
D. equinormal to blood

Explanation

To solve the question "Blood cells retain their normal shape in solution which are:", we need to understand the concepts of isotonic, hypotonic, and hypertonic solutions in relation to blood cells.

### Step-by-Step Solution:

1. **Define the Types of Solutions**:
- **Isotonic Solution**: A solution where the concentration of solutes is equal inside and outside the cell. This means the water concentration is also equal, leading to no net movement of water.
- **Hypotonic Solution**: A solution with a lower concentration of solutes compared to the inside of the cell. Water moves into the cell, causing it to swell and potentially burst.
- **Hypertonic Solution**: A solution with a higher concentration of solutes compared to the inside of the cell. Water moves out of the cell, leading to shrinkage.

2. **Understanding Blood Cells in Solutions**:
- When blood cells are placed in an **isotonic solution**, the concentration of water is the same inside and outside the cell. Therefore, there is no net movement of water, and the blood cells maintain their normal shape.
- In a **hypotonic solution**, water moves into the cells, causing them to swell and possibly burst.
- In a **hypertonic solution**, water moves out of the cells, leading to shrinkage.

3. **Conclusion**:
- Since blood cells retain their normal shape in an isotonic solution, the correct answer to the question is **isotonic to blood**.

### Final Answer:
Blood cells retain their normal shape in solutions that are **isotonic to blood**.