Which of the following conditions is a clear indicator of a polluted or compromised aquatic environment?

When the pH of rainwater is less than ______, it is called acid rain.

Burning of plastics, especially Polyvinyl Chloride (PVC), releases which of the following highly toxic substances into the atmosphere?

Which of the following specific chemical compounds is formed when sulphur dioxide reacts with atmospheric moisture during the sulphur cycle?

Which of the following chemical compounds is formed when atmospheric sulfur dioxide (SO2) undergoes oxidation and reacts with water vapor?

What characterizes the equilibrium relationship between the natural formation and destruction of ozone in an unpolluted stratosphere?

Which air pollutant is formed as a secondary pollutant when primary emissions from wildfires (such as VOCs and NOx) react in the presence of sunlight?

Which group of substances is classified as organic chemical water pollutants primarily introduced through industrial activities and improper waste disposal?

Trichloroethylene (TCE), widely discussed in the context of environmental and public health risks, is chiefly associated with which of the following uses? I. As an intermediate in the manufacture of refrigerants II. As a degreasing agent in metal-processing industries III. As a fertilizer additive in agriculture IV. As a solvent in certain commercial dry-cleaning operations Select the correct answer using the code given below: