Scientists Use Radioactive Dating for wich of the Following

Question

A-Identifying the relative ages of rock layers
B-**determinating the absolute ages of rocks**
C-telling how radioactive substances are
D- collecting evidence of fossils

Wich of the following periods are in order from smallest to largest
A-epoch,period,era
B-epoch,era,period
C-**period,era,epoch**
D-epoch,period,era

Earth's first atmosphere was mainly composed of wich of the following gasses
A-Hydrogen, Helium
B-**Carbon dioxide, oxygen**
C-nitrogen,oxygen
D-carbon monoxide, ozone

Answer 1

I agree after googling
https://www.google.com/search?q=early+earth+atmosphere+composition&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

Answer 2

Do you agree with all of them or just the Carbon one? Also I googled it too and it did say hydrogen and helium as well, so i'm kind of getting mixed answers

Answer 3

I certainly agree with the first two.
I can not do better than just Google the last one.

Answer 4

Kk thanks Damon :)