It is an input and an output. The scanner scans the paper which is the input ,and the output is when the printer prints the paper.
Yes but if the hard drive stops working you will lose your files so it's better to backup your files to a cloud like iCloud by Apple.
The one cell evolved into different categories by adapting to its human/animal/plant’s habitat
None of it passes through. Most of the light is either reflected by the object or absorbed and converted to heat. Materials such as wood, stone, and metals are opaque to visible light.
Good luck