1. the hearts job is to propel blood throughout the body
2. i think the lungs trade CO2 for O2
3. they would go into hypothermic shock or something:p
A. Elevated land area that separates one watershed from another
The correct answer is cells.
Some organisms are single-celled, and are only made up of once cell.
But most complex organisms are made up of billions and billions of cells.
All living creatures are composed of at least one cell.
