Why is the decay of potassium to argon used instead of the decay ...

[nummyann]

Why is the decay of potassium to argon used instead of the decay of potassium to calcium?
 
  A) Calcium is prevalent in too many rocks.
  B) Argon stays in the rock for a longer period of time so it is a more reliable measurement.
  C) Calcium dissolves in water so cannot be measured accurately.
  D) Argon is a reactive element and will only be present due to the decay of the potassium isotope.

Question 2

Why is potassium-argon dating least useful for sedimentary rock?
 
  A) Sedimentary rocks are too rare.
  B) Sedimentary rocks cannot be dated.
  C) Metamorphic and igneous rocks outnumber sedimentary rocks.
  D) Sedimentary rocks don't often contain potassium.

[Chelseyj.hasty]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: D

[nummyann]

TYSM

[kalskdjl1212]

Excellent