Is there any variation in the amount of water present on the earth?

Ans.
No, the total amount of water present on Earth remains almost constant. Water continuously circulates between the oceans, atmosphere, land, and living organisms through the water cycle.

In this cycle, water evaporates from oceans, lakes, and rivers into the atmosphere, forms clouds through condensation, and returns to the Earth as precipitation in the form of rain, snow, or hail. This continuous circulation maintains the balance of water on Earth.