Final answer:
The source of most of the water in Earth's atmosphere is Oceans.
Step-by-step explanation:
The source of most of the water in Earth's atmosphere is Oceans. According to the information provided, Earth's oceans contain 97% of the planet's water, making them the largest reservoir of water. Only 3% of the Earth's water is freshwater, and the majority of it is trapped as ice in glaciers and ice caps.