Which of the following causes mutations at a high rate?

The ultimate environmental hazard to mankind is

The first major problem associated with nuclear energy is accidental leakage. Where have such incidents occurred?

Suggest the effects of radioactive waste and methods for its disposal.

$X$ is a highly potent pollutant and should be buried at a depth of $Y$ meters below the Earth's surface.

Which of the following statement$(s)$ is/are correct?
$(i)$ Nuclear energy is a non-polluting way of generating electricity.
$(ii)$ Radioactive waste leakage incidents occurred at Three Mile Island and Chernobyl.
$(iii)$ Prolonged exposure to radioactive waste can cause cancer.
$(iv)$ Radioactive waste is recyclable.
$(v)$ High doses of radiation are lethal.