there are no B.Arch degrees in canada, only accredited M.arch.  I believe there are 10 universities which offer architecture related bachelor degrees in architectural science/study and each is different from the other... not to mention far away (hint canada is wide).

To answer your questions:

1. Architecture undergrad is very demanding and could easily run 80+ hours of coursework per week, consistently, for many months in a row.  Depending on the quality of university (Waterloo at the top end, UofT on the bottom), you'll get a mix of creative design studios, technical building science courses, physics, and professional practice.
2. You'll need reasonably strong writing and presentation skills as you'll be required to speak convincingly about your work in front of an audience.
3. Architecture is about buildings and design, landscape can, but is primarily concerned with the settings around (ie. plants) or urban hardscape.  
4. You'll need a M.arch to become an intern and log hours towards licensing in Canada.  To get into a M.Arch, you'll need reasonably strong grades, a top notch portfolio, and good time management.

Hi, I'm currently in grade 12 and am looking to apply to a university in Canada. But none of the universities have a B Arch degree. What is the equivalent degree for bachelors in architecture? Also, what is the duration of an M Arch degree? Thanks.

Thank you so much.

Can we be considered architect after having bachelor in architectural studies/science?

In Architecture field , are we able to construct buildings or we have to do civil engineering for that?

What is the difference between Architectural science and Architectural studies? 

The best approach to pursuing architecture as an undergrad in Canada is to check out each of the schools websites for information sessions. While the B.Arch as a professional degree is no longer offered at Canadian institutions, most of the universities that have MArch programs have an undergraduate track that can help prepare you for application into their program or reduce the amount of time needed to complete the professional degree.

As mentioned above the quality of the undergrad options vary as does their focus and time commitment. You can find the list of Canadian architecture program holding schools here. https://study-architecture.ca/...

There are 12 accredited schools, 2 of which are taught in French and one that focuses on Indigenous ways of knowing as a framework for design. The schools are very different at the Masters level in terms of their focus, so it is worth going to as many info sessions as possible. I am not unbiased as I teach at one of these institutions, so I won't comment on which are better. Suffice to say there is a lot of variation in a good way. Also remember that you can always change schools upon completion of the undergrad program.