10 Questions Water: Make a Splash! Splash into this sustainability water quiz! Test your knowledge on sustainable water management and practices. ASU_Sustainability, 04/05/2019 answers Play What percent of the Earth's surface is covered by water? 100% 71% 36% 2% From our global population of 7.7 billion, how many people do not have access to clean water? 7 million people (0.1% of the world's population) 1.75 billion people (23% of the world's population) 2.5 billion people (32% of the world's population) 5 billion people (65% of the world's population) Roughly 12% of land area on Earth is protected, compared to __ of oceans and adjacent seas. 1% 10% 15% 20% … and 7 more awesome questions! Check them out by clicking “Play”.