A common method of producing electricity is from generators with an electromagnet —a magnet produced by electricity—not a traditional magnet. The generator has a series of insulated coils of wire that form a stationary cylinder. This cylinder surrounds a rotary electromagnetic shaft. When the electromagnetic shaft rotates, it induces a small electric current in each section of the wire coil. Each section of the wire coil becomes a small, separate electric conductor. The small currents of the individual sections combine to form one large current. This current is the electricity that moves through power lines from generators to consumers.
The development of an organism — from a fertilized egg, through embryonic and juvenile stages, to adulthood — requires the coordinated expression of sets of genes at the proper times and in the proper places. Studies of several bizarre mutations in the fruitfly, Drosophila , provided keys to understanding the molecular basis of large-scale developmental plans. Early embryonic genes express proteins that set up the orientation and define the body segments of the fly embryo. Then "homeotic" genes act on the segments to make the body parts distinct to each segment.