Hey there!
The answer would be ultrasound.
The ultrasound is considered safe because it uses sound waves for the detection of tissue, organ, baby etc. These waves are considered safe and transfer only a small amount of heat to the tissue in which the ultrasound is done. A little amount of heat is not at all harmful to the body in any means. Early defects of baby can be detected through this procedure, the merits of the process is much higher than its demerits.
Hope this helps !
Energy used since long time ago is a energy production system where the energy is joined with the new resources and alll of that turns into electric energy!<span />
A Fourier analysis is a technique that is able to determine both the amplitude spectrum and the phase <span>spectrum of any signal</span>. This analysis is based on the finding that all sound waves can be derived by adding sinusoids together (so long as the sinusoids are of the appropriate frequencies, amplitudes, and phases).
They analyze the sequence of bases in the DNA to determine who committed a crime.