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

[MirandaLo]

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?

[mirabriestensky]

Answer to Question 1

B

Answer to Question 2

These accretions are called terranes and are fragments of seamounts, island arcs, and small pieces of continents that were carried on oceanic plates that collided with continental plates, thus adding them to the continental margins where mountain building was occurring.

[MirandaLo]

TYSM

[strudel15]

Gracias!