The biggest contributor to ecological footprint is what? (please choose the correct one from the four examples that are down)
1) bikes
2)Recycling
3)Composting
4)Automobiles

What was the first official pair of sister cities?

2/6 of be by to 2/6 is to 24/72 ?

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