Mountains or ocean? Which one do you like better?

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

On nights when we see the new moon phase, what side of the moon are we seeing?

Which countries were controlled by france at the beginning of world war i? hint: use the map in the lesson to you answer this question. algeria burma cambodia indonesia vietnam