Scientists use the amount of radioactive isotopes found in rock and fossils to calculate their ages. this process is called what

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

What is the approximate chemical composition of the solar nebula?

Determine which of the two measurements in each set is lesser.10°f or 20°ca. 10-fb. 20°c