a: parts per trillion ~
b: salt in 5 swimming pools
What:
"parts per trillion half a teaspoon of salt in 5 swimming pools of water"
Useful?
Writer: Mrs X
LCC:
Where:
Date: May 12 2016 6:29 PM
# 9905 Critique Analogy
"parts per trillion half a teaspoon of salt in 5 swimming pools of water"