Topographic Map CAN SOMEONE HELP ME PLEASE

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

The availability and cost of blank is a major component of a region's overall cost of living.marking brainliest answer btw only one answer -health care -transportation -housing -education its 20 pts

Astudent in a skill or trade training program who is learning by gaining experience is a(n) a. mentor b. volunteer c. colleague d. apprentice