A half-life is the amount of time required ____.

A half-life is the amount of time required ____.
 A)to lose one-half of the daughter isotopes
 B)for the mass of a sample to decrease by half
 C)for one-half of the parent isotopes to decay to daughter isotopes
 D)to gain one-half of the parent isotopes
 E)to accurately date a rock sample

Question 2

Parts of many mountain systems are made up of small, accreted lithospheric blocks that clearly originated elsewhere. What are these accretions called and what are they made of?

Question 3

Volcanoes are found at ____________________ plate boundaries and ____________________ plate boundaries.
 Fill in the blank(s) with correct word

Question 4

A rock sample containing an isotope with a half-life of 12 million years has an initial mass of 72 grams. How much of the daughter isotope will be present after three half-lives?
 A)4.5 grams
 B)9 grams
 C)18 grams
 D)54 grams
 E)63 grams

Question 5

What are some ways in which mountains form?