Imagine a glass of your favorite drink that never became empty. Now think about what really happens. You take a drink and there is less in the glass. You keep drinking and soon it is all gone. Good thing you have more to refill your glass. What if there would never be any more of your favorite drink. What would you do? Now you know the difference between renewable and non-renewable. Its too bad that many things here on Earth will run out. This includes some of our natural resources we depend on. Things like oil will not last forever. There is a limited supply. Someday, we will run out, so then what? At current rates of use, coal will last about 300 years. Petroleum will be used up in just a few decades.

What are some non renewable resources that will run out eventually?

What if you could drain all of Earths oceans? What would it look like? You might be really surprised. You see that the surface has two main features. It has continents and ocean basins. Continents are large land areas. These are the areas that are mostly above sea level. Ocean basins extend from the edges of continents. They include the ocean floor and Earths deep ocean trenches. You will also notice the ocean floor is not flat. It too has many Continents are much older than ocean basins. Some rocks on the continents are billions of years old. Ocean basins may only be millions of years old. Because the continents are so old, a lot has happened to them! As we view the land around us, we see landforms. Landforms are physical features on Earths surface. These features change over time, but how? There are actually two types of forces at work.

What are ocean basins?

The digestive system is the body system that digests food. It digest food in two ways, mechanically and chemically. Both help in the process of turning food into nutrients. The digestive system also eliminates solid food waste. The major organs of the digestive system include the mouth, esophagus, stomach, and small and large in- testines. These organs all work together to help you gain energy from the food you eat. Digestion starts in the mouth. When food is swallowed, it travels through the esophagus to the stomach. In the stomach, digestion continues and a small amount of absorption of nutrients takes place. Most chemical digestion and nearly all absorption of nutrients take place in the small intestine. This organ consists of three parts: duodenum, jejunum, and ileum. The large intestine is the last stop in the digestive system. This is where water is absorbed. The food not digested is released as waste.
What is the last organ of the digestive system and what does it do?