The mad per unit volume of a substance is called

Which statements are accurate about snow flakes

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

Name the river that forms a natural border between new york and new jersey and is the site where a passenger jet made a miraculous landing on january 15