the answer is relative frequency ^^
DNA is found in the nucleus of a cell. Depending on the type of cell, different parts of the DNA are used (example; if it's an eye cell, the DNA will use the segment that is dedicated to the functions of the eye). When a protein is needed, the DNA will split and in a process called transcription, the DNA messages are copied onto mRNA. The mRNA then leaves the nucleus through nuclear pores, and then travels through the cytoplasm to locate ribosomes which will produce the proteins needed to express whatever trait it codes for.
Electromagnets can easily be turned on and off.
Explanation:
An electromagnet produces magnetic field which is done by the electric current. These electromagnets contain a wire would like a coil. The current passes through the wire and the magnetic field is concentrated in the center which is the "center of the coil".
When the current is "turned off" the magnetic field "disappears". This shows that we have can have a control over the passage of current or the magnetic field. Thus, the "main advantage" of the electromagnet is that it can be easily turned on and off whenever necessary.
