Water Pollution

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 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 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 _____.

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

The phenomenon of increase in concentration of non-biodegradable organic compounds with each trophic level in a food chain is called