C3 / C4 plants. (Help..)

[Raquel]

Hello there!

I was wondering if you guys could enlighten me. What exactly *is* the
difference between C3 and C4 plants, and how does it affect
photosynthesis and respiration?

Also, I read somewhere that only C3 plants had photorespiration. Why
is that?

Thanks a lot for your help!
Best wishes

**Raquel "Eowyn" Correia**