Question

Please help...
Which of the following gasses was most likely present in earths earliest atmosphere?
Nitrogen Hydrogen Argon Oxygen
There are more questions.. but ill wait to type them.

Answer 1

Hydrogen

Answer 2

thank you:D can you help with the others?

Answer 3

yes i can

Answer 4

what can scientists learn from the rate at which radioactive elements decay?
a rocks actual,or absolute age
the relative age of rock layers
where one soil horizon ends and the next begins
the difference between molds and casts

Answer 5

the 1st one

Answer 6

the relative age of a rock is
its age based on how much carbon-14 it contains
its age compared with the ages of other rocks
less than the age of fossils it contains
the number of years since it formed

Answer 7

2nd one

Answer 8

earths atmosphere,oceans,and continents began to form during the first several hundred million years of precambrian time. True or false
A mold forms when minerals replace all or part of an organism. True or False

T

Answer 9

false and true

Answer 10

How are mold and cast related?

Answer 11

I got this one^^ if you want you want to answer i can maybe improve my answer.

Answer 12

Thanks so much:D