Misc: According to experts, 30 percent of all marriages occur because of -------------?

Questions

What is the lowest level of the Earth's atmosphere called?

In India, and also the British forces, what job does a Dhobi Wallah do?

What is the correct chemical name for iron pyrites, sometimes known as 'Fool's gold'?

What radioactive element is used to power modern heart pacemakers?

In October 1999, who replaced Frank Dobson as Secretary of State for Health?