An electronic kit might be useful for many purposes. An example is if a wire gets disconnected for some reason and needs to be soldered back together.
It isn't "the best"; it is useful for some specific purposes.
None. Although for some purposes, it can be useful to assume it has infinitely many corners.
Many things are not necessary. Some of them, like fast cars, serve useful purposes.
francium is a rare element but might be useful in some ways.
Some general adaptations for flowering plants having visual and olfactory cues. These are useful for purposes of attracting pollinators.
For most purposes, floppy disks are no longer considered important or useful. They have been supplanted by newer and more reliable forms of storage. For some people with legacy equipment that they cannot replace, such as older electronic keyboards, sewing machines, or industrial equipment, floppy disks are still required.
It is brittle, so no good under tension. It's better under compression.
No one *needs* gold, but people value it because it is pretty, and nice and shiny. Also as it does not corrode, it is useful in some electronic devices.
Some hosting companies include www.webs.com, www.ucoz.com, and www.bravehost.com. Blogging websites are also very useful for some purposes of a website.
Some products for mosquito killers are electronic traps, dunks and sprays. One of the most useful techniques for killing mosquitoes is by spraying them pyrethin and water.
You should get your niece an electronic PDA or some sort of method for keeping track of daily activities. Focus on organization and healthy life style promoting gifts.
The power strokes occurring inside the cylinders of internal combustion engines.