Blood is isotonic with:

Options

A. `0.16 M NaCI`
B. Conc. `NaCI`
C. `30% NaCI`
D. `50% NaCI`

Answer

To determine which solution is isotonic with blood, we need to understand what isotonic means. An isotonic solution has the same osmotic pressure as the blood, which means it has the same concentration of solutes.

### Step-by-step Solution:

1. **Understanding Isotonic Solutions**:
- An isotonic solution has the same concentration of solutes as the blood plasma. This prevents the movement of water into or out of the cells, maintaining their shape and function.

2. **Identifying the Options**:
- We have four options to consider:
- A) 0.16 molar NaCl
- B) Concentrated NaCl
- C) 30% NaCl
- D) 50% NaCl

3. **Analyzing Each Option**:
- **Option A (0.16 molar NaCl)**: This concentration is known to be isotonic with blood.
- **Option B (Concentrated NaCl)**: This is typically a much higher concentration than isotonic, hence it would cause cells to shrink (hypertonic).
- **Option C (30% NaCl)**: This is also a very high concentration and would be hypertonic to blood.
- **Option D (50% NaCl)**: This is an extremely high concentration and would definitely be hypertonic.

4. **Conclusion**:
- The only option that is isotonic with blood is **Option A (0.16 molar NaCl)**.

### Final Answer:
- Blood is isotonic with **0.16 molar NaCl** (Option A).