On the earth planet, most of the non-saline water exists as ice caps and glaciers. The largest part of the remaining non-saline water is found as

Correct Answer: C) Groundwater

Let's break down why:

Groundwater constitutes the largest reservoir of freshwater after ice caps and glaciers. Approximately 30.1% of the world's freshwater is found underground. This is a significant amount, crucial for sustaining ecosystems and human populations. A) Humidity and clouds in the atmosphere: While atmospheric water is vital for the water cycle, the total volume of water held in humidity and clouds is relatively small compared to groundwater. It's a transient reservoir. B) Non-saline water lakes and rivers: Lakes and rivers hold a substantial amount of freshwater, but their combined volume is significantly less than that of groundwater – only about 0.3% of the world’s freshwater. D) Soil moisture: Soil moisture is important for plant life, but the quantity of water stored in the soil is far less than groundwater. It's a very small percentage of the total non-saline water. Therefore, after ice caps and glaciers, groundwater is the largest remaining reservoir of non-saline water on Earth.