Much of earth's water supply likely originated from where? group of answer choices asteroids. transpiration. the respiration of early organisms. gases expelled from the sun, i. e., solar wind.

Asteroids                

Explanation:

Much of our earth's water supply comes from the asteroids.

More research done suggested that much of the earth's water is being delivered by the asteroids.

The origin of earth's water can be tracked down by analyzing the ratio of the two isotopes of hydrogen molecule. On isotope is the ordinary  hydrogen and the other is the deuterium.

Research and study suggests that there is a close match between the earth water's ratio of deuterium to hydrogen to that of the asteroids, which is rich in water and elements such as nitrogen and carbon.

Thus the answer is ---  "Asteroids"