The first thing I'd look for is rear suspension. MTBs are pretty much the only bikes equipped with that. Next I'd look at the wheels. If it has wide, knobbly tires, odds are it's a MTB. This isn't 100% though, as there are narrow, smooth tires that'll fit a typical MTB rim as well.
Then I'd look at wheel size. Most common for MTBs is 26", AKA 559 mm. Wheel size will be written on the tire sidewall.
Next is the handlebars. MTBs will have either what's called a flat bar or a riser bar. What these two have in common is that the grip part will be pointing almost straight to the side. When you hold it your knuckles should be pointing forward. If the grip part is curved way back (with your knuckles turned pretty much sideways), then it's probably not a MTB.
Brakes: These days most MTBs will have disc brakes.
Frame: MTBs are meant to be able to take some abuse, or at least to look the part, so frame tubing on a new-ish bike will be thick and chunky.
The bmx thruster rampage bike is a exellent bike
Is the Scan R10 a good bmx bike for doing tricks on
a bmx bike
yes
BMX
Wethepeople bmx bikes are excellent, probably the best
If you jumped that bike it would crack.
Yep
A BMX bike is good for both boys and girls, as long as they want to do BMX-style riding, with jumps, tricks and that. If you don't want that, there are several bike types that are better, more comfortable, and more efficient for general riding-around type of use.
you can find a BMX bike in halfords
Yes its a fantastic bike and great for tricks
No way to tell. It will depend on what you expect from the bike, how much you are willing to spend, what currency you're talking about, if you intend to buy new or used, etc etc.