Animals range in size from no more than a few cells to organisms weighing many tons, such as blue whales and giant squid.
Most animals inhabit the seas, with fewer in fresh water and even fewer on land.
You must learn to say these seven levels of classification in their proper order. I recommend that you say them OUT LOUD and OVER and OVER . Before you know it, you will have them memorized in a very useful form. Click here to see how sponges are built. Tell how medusae and polyps are different from one another.