The slow twitch muscle fibres have a higher count of mitochondria which means it can process quicker, it receives a energy, it receives a good blood supply since it has a high amount of capillaries, which means it has a good supply of oxygen, which helps to maintain the use of the aerobic energy system for longer, making type 1 fibres more effect for endurance, while the type 2 fast twitch have less mitochondria and rely more on glycolysis.
The cranial cavity and the vertebral canal contain the spinal cord
Vertebrae is the synonym of spine. Inside the spine, there will be spinal cord protected by the nearby bone. Spinal cord will divided into many smaller cords after leaving the spine and spread through the body to carry signal from/to the brain. Without the spinal cord, the brain will not be able to reach and control the body.
Its Light because it reacts to photosynthesis