upper case
The US spelling is "capitalization" (upper case, or financial basis). The non-US (British-English) spelling is "capitalisation".
1024 MB= 1 GB Mega is always given an upper case M and Byte is always given an upper case B as is Giga.
It is not necessary to capitalize the word mainland. The sentence is fine with mainland in lower case, while North America is in upper case.
The letters "sp" (either in lower or upper case) can have several different meanings. Sometimes it is used by an editor to note a spelling error. In upper case (SP) it can stand for Shore Police (to the navy), or (to a Scientologist) Suppressive Person.
I am on the estate. Note: the upper-case 'I' should always be used when referring to yourself, not the lower-case 'i'.
Artistic license, nothing else. The same stylistic spelling was used on Mercury dimes, among other coins.
upper case
the spelling for pencil case in french is "une trousse".
It is simply something done by the creator. It is an artistic statement, or so they say.
Both. "Case sensitive" means that upper case and lower case characters are treated as different characters.
Upper and lower case came from when everything used to be printed by hand. The letters would be inside of a brief case. The upper case would be kept on the top of the case and the lower case on the bottom.