What is the main source of heat energy in Earth's inner core?

A. friction

B. solar energy

C. radioactive decay

D. electromagnetic radiation

Which of the following can increase as a result of stratospheric ozone depletion and can contribute to the melting of glaciers?

A. radioactive decay

B. ozone accumulation

C. the intrusion of magma

D. incoming solar radiation

1. C. Radioactive decay

Earth's main source of heat energy in inner core is that produced due to radioactive decay of isotopes in mantle and crust. The major heat-producing isotopes in the earth's crust are potassium-40, uranium-238, uranium-235 and thorium-232.

2. D. Incoming Solar radiation.

Ozone is a protective layer in earth's atmosphere which protects it from harmful ultraviolet radiations present in solar energy. With depletion of ozone, percentage of ultraviolet rays entering the earth increases or the incoming solar radiation increases and hence has its harmful effects on earth