Questions

Milk is not a pure substance since it has so many constituents that can be separated physically.

Compounds are pure substances formed from elements unlike mixtures.

Total Output is a synonym for Aggregate supply or Initial production.

It gets contaminated by lead

Panacea, also known as panchrest, is a medicine supposed remedy that is claimed to cure all diseases and prolong life indefinitely. It is named after the Greek goddess of universal remedy Panakeia.

Based on conventionality in deriving energy, energy sources could be classified as

Conventional ::

coal, oil, hydro, nuclear, etc... sources which can be used up or exhaustible.

(and)

Non - conventional ::

solar, wind, tidal, geothermal, biogas, etc... sources which are not exhausted.

Among the given options, Geothermal energy is the alternative energy source among all the choices that are given in the question, that is exhaustible.