Read the statements related to the earths environment. Which statements are TRUE?

I. Water vapour, and not carbon dioxide, is the most prevalent greenhouse gas in the earth's atmosphere.
II. Besides China and the United States, India and Brazil are the highest greenhouse emitting countries.
III. Although about 70% of the Earth is covered by water, and there is more beneath the surface, only about 5% of earth's water is fresh, liquid and found above ground.
IV. Globally birth rates are fluctuating, people are living longer and the total population is increasing.