The food ingredient that is important for brain development is GLUCOSE.
Glucose is the only type of nutrient that the brain can use to carry out its biochemical activities. The brain usually use about 20% of the glucose content that is available in the blood. Absolute lack of glucose for brain use can cause one to go into coma.<span />
Thermal energy to Gravitational PE to Kinetic energy.
Based on their cell type, their ability to make food, and the number of cells in their bodies.