This type of question come in our exams usually that.

If the Reaction
P+Q → R + S
is described as being of zero order with respect to P, it means that.
Answer: THE RATE OF REACTION IS INDEPENDENT OF THE CONCENTRATION OF P.

I want to ask that, what is such thing in this reaction that we should write this answer , I mean how to solve it or what , thanks i have MCAT exams please reply

2 answers

http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Rate_Laws/The_Rate_Law

What you need is to understand what" if rate of reaction is such that
R=kP where k=1, that is zero order. See the reference above
@bobpursley , thanks but i have very little time left for exams so summarize to me in simple way if ur wish bro, tell me how to solve such questions quickly?