Salt concentration (salinity) of the sea measured in parts per thousand is

Options

A. `10 - 5`
B. `30 - 70`
C. `0-5`
D. `30 - 35`

Explanation

To determine the salt concentration (salinity) of the sea measured in parts per thousand, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Salinity**: Salinity refers to the concentration of salts in water, typically measured in parts per thousand (ppt). This is crucial for aquatic organisms as it affects their survival and distribution.

2. **Identifying the Range of Salinity in Different Water Bodies**:
- Freshwater has a salinity of 0 to 5 parts per thousand.
- Inland waters generally have a salinity of 5 to 10 parts per thousand.
- Sea water typically has a salinity ranging from 30 to 35 parts per thousand.
- Hyper saline water bodies can have salinity levels ranging from 30 to 70 parts per thousand or even higher, but these are not typical for normal sea water.

3. **Focusing on Sea Water**: Since the question specifically asks about the salinity of the sea, we will focus on the typical range for sea water.

4. **Conclusion**: The normal salinity of sea water is generally found to be between 30 to 35 parts per thousand.

### Final Answer:
The salt concentration (salinity) of the sea is generally between **30 to 35 parts per thousand**.

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