What can scientists infer about the period of very early Earth from the lack of fossilized remains of oxygen breathing animals and the dominance algae?
A)everything was underwater
B)the atmosphere lacked oxygen
C)only fish lived during that time
D)the dinosaurs used all the oxygen

The correct answer is B) the atmosphere lacked oxygen.

Explanation:

A is incorrect because not everything was underwater.C is incorrect because not only fish lived during the time. D is incorrect because dinosaurs could   not have used all the oxygen.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.