AFAIK, cobalt isn't necessary for plants. It is however required for animals.
Good stuff
No, cobalt is not meant to be ingested as it can be toxic to humans. Small amounts of cobalt are found naturally in foods like plants and dairy products, but it should not be consumed in large quantities.
There is just one Cobalt compound on living things (animals and not plants) and is the Cyanocobalamin (B12 vitamin)
The purpose of cobalt blue glass is to filter out ultraviolet and infrared light while allowing visible light to pass through, making it ideal for protecting sensitive materials from light damage or for decorative purposes.
Cobalt (II) phosphate or cobaltous phosphate.
Yes, cobalt form many chemical compounds as cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt sulfide, etc.
Photosynthesis
There are no compounds in Cobalt. It is completely impossible, because Cobalt is an element, and compounds are made up of elements. If this is what you meant to ask, then there a a lot of compounds with Cobalt in them. One example is Cobalt (III) Fluoride, chemical formula CoF3. Any compound with a "Co" (the "C" must be capitalized and the "o" must lowercase) in it contains Cobalt.
Yes, cobalt form many chemical compounds as cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt sulfide, etc.
Yes, cobalt chloride and cobalt dichloride refer to the same compound. Cobalt chloride is also known as cobalt(II) chloride or cobalt dichloride, as it consists of one cobalt ion and two chloride ions.
cobalt = Cobalt/Kobalt
Cobalt wheels are used on bikes. These cobalt wheels are much stronger that the usual ones when you buy your bike. They can stand more force, incase you should fall with your bike, the won't bend or break that easily.