The abundance of oxygen and ozone in Earth's atmosphere can be ...

[EY67]

The abundance of oxygen and ozone in Earth's atmosphere can be explained only through biology.
 
  Indicate whether the statement is true or false

Question 2

Although it is difficult to tell from our vantage point inside the galaxy, astronomers suspect that the Milky Way is a barred spiral.
 
  Indicate whether the statement is true or false

[Chelseyj.hasty]

Answer to Question 1

TRUE

Answer to Question 2

TRUE

[EY67]

Gracias!

[bitingbit]

Thanks for the timely response, appreciate it