Guys, I am currently applying for Canadian universities
And I admit myself that I am not really an academically strong type of a student
But I really do plan on Life sciences in UBC, UofT, McGill, university of Waterloo, York
I would accept any if I am admitted in 
So, my point being is how competitive are those universities to get accepted?
I do not really have much of any prior informations about minimum requirements.
Are you American? You should take a look at the minimum requirements at McGill: http://www.mcgill.ca/applying/admissionsguide/standards/unitedstates
For Life sciences, you need an A- average junior and senior year, an A- in prereqs (2 of Biology/Chem/Physics, Precalculus). You also need a 30 ACT or 680 on each section of the SAT I and certain SAT IIs (2 of Physics, Bio, Chem, Math I, Math II).
Life sciences is one of their, if not the most, competitive major. McGill is heavily numbers-driven; if you meet these requirements, you have a good chance at admissions, if not, your chances of admittance are very slim.
I don’t really know anything about the other Canadian universities.
Good luck!
^or… if you meet these requirements, you’ll warrant a review. If you don’t meet these requirements, you won’t even get reviewed. (Happened last year for 10 points off in Math). In addition, when they say “minimum”, they really mean they want to see much higher. However they give themselves some leeway if you do meet the requirements.
Most course requirements are listed on each university’s website. If you’re an American, you’ll likely be required to submit SAT I scores as well, but I don’t recommend applying for Canadian unis as a US citizen just because you have lower marks.
Canadian universities mainly look at your top 6 senior grades (some of them look only at the grades in the prerequisite subjects, otherwise they will take any 6 grades as long as you completed the necessary courses). Generally you need to have at least a mid-80 average. A lot of the more competitive programs/schools such as Waterloo have recently made their application process more holistic with the AIF, which could help compensate for your weaker grades, but you still generally want to be well over the minimum requirement.
yconic is essentially the Canadian version of CC. You could check out their forums for more in-depth info on Canadian admissions.