Russia is ranked what in the worlds argest land are of a country

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

What structure on the south african coast has a range of 63 km and releases flashes every 30 seconds?

How does central place theory explain patterns in the size and distribution of cities?