Lets say you lived in a gravitational experimental room

Would you think it'd be easier to move around?
Would you jump higher?
Would your physical appearance change?

However, from knowing how much of human blood is made up of Iron, and other physical compounds. It's unclear to say if you will die from being in this facility for too long. The iron in your blood might weigh down on your vains and cause you to bleed internaly. The food you eat may cause you to have multiple ulcers, and you might not be able to use the washroom due to major injuries due to the high gravity.

1) No. Your muscles are undeveloped and no longer fit to withstand the greater effect of gravity. If you sat in a chair for 12 hours, you wouldn't be able to stand normally without wobbling your first few steps.
2) No. Undeveloped muscles as explained in #1. If anything, you'd jump higher when you were back in the anti-gravity chamber for obvious reasons.
3) Yes. You'd be a little taller from not having the effects of gravity on your spine. This is already evident from people being slightly taller in the morning than they are when they hit the hay.


Edit: mistook the idea of "increased gravity" with "decreased".

Not sure how you came up with the idea of iron in your blood poking through your veins and killing you in a glorious iron riot within your blood stream... unless the anti-gravity facility used a giant magnet which sucks iron out of you until you look like a human blood sprinkler. If the effects of gravity on your entire body is small, the effect of gravity on those iron molecules are proportionally less as well and vice-versa.

It's gunna be like natural selection. The strong people who are fit can adapt a little, and then their kids might be able to adapt to a smaller degree higher gravity, and so on.

Natural selection is less about adaptation and more about the ability to procreate. While it is true that if one is more "adapted" to an environment, one is more likely to successful procreate, however favorable traits that one learns or "adapted" during one's lifetime does not get passed onto their offspring. For instance, if you work out and become athletic, you may be more fit to survive but your child will not gain the athletic abilities. Those traits of athleticism are "acquired" through randomization in the gene pool (Darwin's theory of evolution); favorable traits (such as athleticism) allow the organism to survive and pass on those traits.