Does vapeing effect babys if they do it

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.

Which type of seismic waves are confined at the surface