1- How many regions of operation does a bipolar junction transistor have and which region has to dissipate the most heat
2- In a biopolar junction transistor, collector current is controlled by what? a-collector voltage b-base current c-collector resistance or all of the above

 

These sound like homework questions.

All of these answers can be obtained using google.

hgmjr

 

Do you have a textbook?

 

This may be helpful:
http://www.allaboutcircuits.com/vol_3/chpt_4/index.html

 

3 regions of operation : 1) Saturation 2) Cut-off 3) Active
It basically acts as a switch in first 2 regions of operation and an Amplifying action takes place in the third region.It is a current controlled device as a base current (Ib)controls the collector current(Ic) in case of CE (Common Emitter )configuration. search wikipedia http://en.wikipedia.org/wiki/Transistors for general information.