The largest source of available freshwater on earth is

lakes
rivers
aquifers
ice caps

The correct answer is ice caps.

Explanation:

Ice caps are the largest source of available freshwater on Earth; especially in Antarctica.  

ice caps is the correct answer.

Explanation:

The largest source of available freshwater on Earth is ice caps.

Freshwater is a naturally occurring water and concentration of the dissolved salts is low.

Fresh water carries water in ice caps as the largest sources and water in glaciers, ponds, lakes, streams, rivers, ice sheets.

Antarctica contains 90% of the fresh water on the Earth's surface but it is iced in the form of the ice caps.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.