A_ is a part of the DNA code on a chromosome.

The 5th term in a series of even number that begin 3x

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

Distance that the transcontinental railroad covered from omaha to san francisco.