Rainwater harvesting from roofs is a simple and environmentally friendly way to supplement household water supply.

The given figure shows a river and the types of land use on the sides of the river. The water quality of the river  was studied by measuring the amounts of dissolved oxygen and ammonia in the water collected at sites $X, Y$ and $Z$. The results are given below:

Which of the following is correct regarding this?

The given graph shows changes in concentration of two substances $X$ and $Y$ in river polluted by sewage. Which of the following options most appropriately identifies $X$ and $Y$?

The given graph shows the amount of pollutants in four rivers $P, Q, R$ and $S$. The river that can continue to support the most number of aquatic plants and animals is _____.

Water pollution involves

The following table shows mercury concentration in various organisms living in the same terrestrial habitat.

Now, select the correct food chain interlinking these organisms, that will exist in the ecosystem.

Select the option that correctly identifies $X$ and $Y$ in the given flow chart.

Match column I and column II and select the correct option from the given codes.

Refer to the given diagrammatic representation of the distribution of water on Earth and select the correct statements for $X, Y$ and $Z$.

(i) $X$ is a persistent body of dense ice that is constantly moving under its own weight.
(ii) $Y$ is found below the water table and rainwater is its main source.
(iii) $Z$ is an important source of water to the perennial rivers.

Select the option that correctly identifies $X$ and $Y$ in the given flowchart.