Human activities caused great damage to the ozone layer. motivate/Substantiate this statement​

Which state has the highest killing rate?

Which continents lie only in the northern hemisphere

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