The document discusses various topics related to oceans including their size, depth, threats, and food chains. The ocean covers over 70% of the planet's surface and has an average depth of over 4,000 meters. Animals in the ocean must deal with predators, including humans, as they search for food. Threats facing the oceans include oil spills, overfishing, and garbage. Food chains and webs show how different ocean creatures obtain energy and nutrients.