In order for you to prove your educated guess you need to

What percentage of the earth's water is available for use by living things?

When your working with the passage-based reading questions on the psat do all of the following except. a)make sure you read each question throughly. b) try to answer each question before you look at the answers. c) plan to spend most of your time reading the passage. d) make sure your answer choice is the most correct number me

What is the leading cause if water scarcity throughout much of the world