മനുഷ്യ ശരീരത്തില് ഏറ്റവും കൂടുതല് ഉള്ള മൂലകം:
Demography is the study of:
Light year is the unit of:
Theory of relativity is associated with:
The instrument to test the purity of milk?
The study of relation of animals and plants to their environment?