Lakes and rivers constitute

a.87% of freshwater

b. a tiny fraction of earth’s freshwater

c. a majority of earth’s freshwater

d. a majority of water on earth

Perhaps surprisingly, lakes and rivers constitute a tiny proportion of the world's total freshwater, so answer (b) is correct. Most of the freshwater on our planet is in fact locked up in ice and glaciers, some 68%. The majority of the rest, 30%, is actually underground, in springs and other groundwater feeders. That leaves just 2% that makes up all the rivers, lakes, ponds and other visible freshwater reservoirs that we see in our day-to-day lives.