Natural Selection

The Heart

Watch blood flow through two separate circuits — lungs and body.

Osmosis

Water moves through a partially permeable membrane — from dilute to concentrated.

Enzymes

Change the temperature or pH — see what happens to the enzyme's active site.

Mitosis

Step through the stages of cell division — one cell becomes two.

Foods Chain

Build a food chain — see how energy shrinks at each level.

Food Chains