Reading Metrics
Grade Level
Upper Grades (UG 9-12)
Book Level
7.6
Points
4.0
Fiction/Nonfiction
Nonfiction
Word Count
21113
Points per Word
0.000189
Description
Cells are alive, and they're what life is made of. Four billion years ago a single cell kickstarted all life on Earth. Today, your body is made up of over 30 trillion cells, every one of which is teaming with activity.