The human body is made of many parts. All of these parts are essential for function to be normal. Some of the parts in the body are more essential than others. For example, the brain is an organ that is vital for the rest of the body to work. The brain is in the head. The heart is another organ of great importance. the heart is like a bomb than sends blood to other parts of the body. The stomach is an organ that helps the digestive system. If you don't take care of it you could suffer from infections. There are some parts of the body that are important but not essential like, arms, legs, knees, knuckles, and hands. These parts just help with normal movement and help us with everyday activities like school and sports.
I am a native Spanish speaker from Mexico. I know what I'm doing. :)