The eutrophication of water body results in ...... .

Chlorine atoms act as catalysts in the depletion of the ozone layer in the Earth's atmosphere. These chlorine atoms originate from which of the following?

$A$ man uses municipal water. Due to water scarcity,he starts using groundwater. He experiences a laxative effect. What could be the reason for this?

The concentration of dissolved oxygen $(DO)$ in cold water can go up to ......... $ppm$.

The $10\%$ energy transfer law of food chain was given by

$A.$ Ammonium salts produce haze in the atmosphere.
$B.$ Ozone is produced when atmospheric oxygen reacts with chlorine radicals.
$C.$ Polychlorinated biphenyls act as cleansing solvents.
$D.$ 'Blue baby' syndrome occurs due to the presence of excess nitrate ions in water.
Choose the correct answer from the options given below: