Which one of the following should contain maximum DO?ans.RiverGround waterLakemolten glacier and ice caps

The question is asking which one of the following should contain the maximum Dissolved Oxygen (DO):

1. River
2. Ground water
3. Lake
4. Molten glacier and ice caps

Dissolved Oxygen (DO) is the amount of oxygen that is present in water. It is an important measure of water quality as it indicates a water body's ability to support aquatic life.

Here is a step-by-step analysis:

1. River: Rivers often have high levels of DO because they are shallow, fast-moving, and often turbulent, which helps to mix oxygen into the water.

2. Ground water: Ground water typically has lower levels of DO because it is not exposed to the atmosphere and therefore has less opportunity to absorb oxygen.

3. Lake: Lakes can have varying levels of DO. Surface water in lakes is often well oxygenated, but deeper water can have lower levels of DO because it is not mixed as thoroughly with the atmosphere.

4. Molten glacier and ice caps: Glacial meltwater can have high levels of DO because it is often cold (cold water can hold more DO than warm water) and because the process of melting can introduce oxygen into the water.

So, the answer to the question would be that rivers and molten glaciers and ice caps should contain the maximum DO. However, the exact levels can vary depending on a number of factors, including temperature, salinity, pressure, and biological activity.