Medical Dictionary. brachial plexus. noun. Medical Definition of brachial plexus. : a complex network of nerves that is formed chiefly by the lower four cervical nerves and the first thoracic nerve, lies partly within the axilla, and supplies nerves to the chest, shoulder, and arm.
Nonrenewable Sources of Energy. Most of the energy we use comes from fossil fuels, such as coal, natural gas and petroleum. Uranium is another nonrenewable source, but it is not a fossil fuel.Uranium is converted to a fuel and used in nuclear power plants.Once these natural resources are used up, they are gone forever.nergy is the power we use for transportation, for heat and light in our homes and for the manufacture of all kinds of products. There are two sources of energy: renewable and nonrenewable energy.
1 Fire is an event, not a thing. Heating wood or other fuel releases volatile vapors that can rapidly combust with oxygen in the air; the resulting incandescent bloom of gas further heats the fuel, releasing more vapors and perpetuating the cycle. 2 Most of the fuels we use derive their energy from trapped solar rays. In photosynthesis, sunlight and heat make chemical energy (in the form of wood or fossil fuel); fire uses chemical energy to produce light and heat. 3 So a bonfire is basically a tree running in reverse. 4 Assuming stable fuel, heat, and oxygen levels, a typical house fire will double in size every minute.