What other gas would most likely also have different amounts in inhaled and exhaled air?
ozone (o3)
hydrogen (h2)
water vapor (h2o)
sulfur dioxide (so2)

The correct answer would be water vapors (H₂O).

The concentrations of three main gases change in inhaled and exhaled air. These gases are oxygen, carbon dioxide, and water vapors (H₂O).

The inhaled air contains a very small amount of water vapor, however, the exhaled air is saturated with water vapors.

Our body saturates the inhaled air with moisture as it helps in gaseous exchange at the alveolar site. Dry air can damage the alveolar membrane.

on island x the species needed to adapt because they were being subject to predators which didn't inhabit island y.  

answer; lower are;