NO
If you were pregnant then you wouldn't menstruate at all. Menstruation only occurs if there is no pregnancy, if you menstruate you're not pregnant.
It is biologically impossible to menstruate if you were pregnant.
Yes
If you menstruate then you're not pregnant - it is possible to bleed while pregnant, but it is biologically impossible to menstruate while pregnant. The very earliest you can tell when you're pregnant or not is 3 weeks after you had sex, via pregnancy test.
how would someone is pregnant not menstrate
This makes no sense - you only menstruate if you don't fall pregnant. It's also unlikely you'd be fertile so close to when you were due to menstruate.
No, it is biologically impossible to menstruate while you are pregnant.
No, it's biologically impossible for a woman to menstruate while she is pregnant - a woman will only menstruate if she doesn't get pregnant during the last cycle. A woman can bleed during pregnancy for various reasons but this is fairly rare, chances are if you're menstruating you're not pregnant.
Yes, Menstruation can also occur while pregnant, unless if she has menstruation disabilities.
I had three period when I was pregnant with my first so it is possible but very rare! :-)
Typically, a woman of childbearing age should menstruate every 28 days or so unless she is pregnant or moving into menopause.