You find a rock that contains equal amounts of potassium-40 and argon-40. how old is it?

Modern weaponry has increased the number of deaths in wars and violent conflicts.

How do you know when a chemical reaction has occurred

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)