Alpha particles bouncing off gold foil in Rutherford's gold-foil experiment which developed the understanding of the structure of the atom, expanding upon Thomson's research with cathode rays.
The same principle apply to stereo microscopes, a 10X eye piece combined with a 4X objective lens will produce 40X magnification.
It is free to bind to another promoter and begin transcription.
Autorhythmic, contractile, cardiac
I think the classification is taxonomy