The Human Body -

The spinal cord acts as the main data cable, transmitting instructions from the brain to the rest of the body. This system is so fast that we can react to pain or heat in a fraction of a second, often before our conscious mind even registers the sensation. The Chemistry Lab: Digestion and Metabolism

Every cell needs oxygen to produce ATP (energy) and must eliminate carbon dioxide, a waste product. The respiratory system makes this exchange possible. Air enters through the nose or mouth, travels down the trachea, through the bronchi, and finally into millions of tiny air sacs called alveoli. The lungs contain about 300 million alveoli; if flattened out, they would cover a tennis court. The Human Body

The human body is an intricate, highly coordinated biological system composed of trillions of cells working in perfect harmony. From the microscopic firing of neurons to the mechanical pumping of the heart, every aspect of our physiology is optimized for survival, adaptation, and interaction with the world. The spinal cord acts as the main data