Need Some BIS Gyaan

Hi,

I've a few queries regarding Blackberry Plans :

a) Can we browse Web via Opera Browser without activating BIS?

b) Do we need to activate BB Social Plan for accessing FB & Twitter via Opera Browser?

c) Please name those stock Apps/Services that requires BIS to work.

d) Is BB App World accessible without BIS?

Regards.

Please Reply...(I know that nobody is interested in Blackberry's).