Describe when a light bulb is turned on, the electric current in the filament causes the filament to become hot and glow. if the filament is surrounded by gas, describe how thermal energy is transferred from the filament to the air outside the bulb.

Electric current passes through a filament of an incandescent bulb, thereby increasing it temperature. When current flows, it contains electrons through the filament to produce light. Typically, incandescent light bulb consists of a glass enclosure that contains tungsten filament. The glass enclosure contains either a vacuum or an inert gas that serves as the filament protection from evaporating. Incandescent light bulbs contain a stem attached at to its base to allow the electrical contacts to run through the envelope without gas or air leaks. 

c

explanation:

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.