A fatherboard :P
A fatherboard can be plugged into a motherboard. They can both support one or more child boards. Two motherboards can be connected with a special adapter. Fatherboards can fit directly together, but only when one is placed backwards.
Riser
riser
It is called motherboard because all the daughter cards are installed or placed in the mother board. So unless there is a motherboard, there is no role of daughter boards
LGA
Why dont you read the book instead of Googling =P
Just below where the CPU is located under a heat sink. Although most modern motherboard don't have north bridges and south bridges and instead are combined into a single chipset.
Yes, some manufactures (mostly OEM) call use "system board" definition instead of "motherboard" (custom builds).
If a motherboard is installed without the use of standoffs (the yellow-gold colored heads) and instead is mounted directly to the case, then the motherboard will end up not working. It may be a temporary problem (put the standoffs in and remount and it works) or you may get to buy a new motherboard (FZZZZT POP!)
Usually, when you buy a computer case it comes with standoffs which get screwed on to the case (there's usually at least 6 and as many as 10) and then the motherboard sits on those standoffs instead of on to the case itself. The motherboard standoffs serve the purpose of avoiding direct contact between the motherboard and the case itself so as to avoid a possible electrical discharge which would in turn damage the motherboard. There are holes on the case where the standoffs should be placed.
The motherboard is main part of CPU. All parts do connect with motherboard.