k thanks
a)
Port A is usb, used for mice, flash storage devices
Port B is firewire, used for portable harddrives and video editing
Port C is Mini ps/2, used for older mice and keyboards
Port H is parralel port, used for printers (someone correct me on that?)
b)Firewire
Firewire (also known as DV or i.Link) is commonly used in video capture and editing because of its high speed. Data is transfered at speeds of up to 400mbps (800mbps can now be achieved with firewire 800), which is fast enough to handle tranfer of high quality video from a video camera to the computer. Other mediums such as USB cannot compete due to their inconsistent speed.
c) Not too sure on this one, someone with a student answers booklet?
EDIT: question C ideas can be found here:
http://forums.whirlpool.net.au/forum-replies.cfm?t=264481&p=-1#bottom