The study of ______ shows that there is significantly more carbon ...

[EY67]

The study of ______ shows that there is significantly more carbon dioxide in the earth's atmosphere than at any time in the last 800,000 years.
 
  a. ice core data
  b. earth's electromagnetic field
  c. aurora borealis analyses
  d. coral reefs
  e. eyes chordata

Question 2

________ is the most significant contributor to global warming. We currently release 35 billion of this substance into the atmosphere every year.
 
  a. O2
  b. O3
  c. U2
  d. H2O
  e. CO2

[Jossy]

Answer to Question 1

A

Answer to Question 2

E

[EY67]

Thanks for the timely response, appreciate it

[adf223]

Gracias!