Which scientist is credited with developing the first successful smallpox vaccine?

Which parasitic disease transmitted by mosquitoes causes recurring fever and chills due to infection of red blood cells?

Which gas is most abundant in the Earth's atmosphere?

Which gas is primarily responsible for causing the bends in deep sea divers who ascend too quickly?

Which everyday observation demonstrates the concept of inertia in physics?

Which vitamin is primarily synthesized in human skin upon sunlight exposure?