Characteristics and Organization of Life
A rabbit moves and responds to its surroundings. A dormant seed may do neither visibly, yet both are alive. To judge life, examine cellular organization and biological processes across an appropriate time scale, rather than choosing one conspicuous behavior. The same approach also helps you distinguish levels of organization: a cell, an organ, and a […]
Solutions and Separating Mixtures
Not everything is a pure substance. Most of what you meet each day, from ocean water to the air, is a mixture, and mixtures can be pulled apart again by simple physical methods. Knowing how solutions form and how to separate a mixture is practical chemistry that shows up on nearly every science test. This […]
