Colonizing Mars

so in my environmental geology class, my team and I have to do a project which focuses on two options. option one is to colonize mars and the second option is to mine mars. moreover, my team picked to colonize mars. so my part is to do research on the following. which should take at least a page

1) why mining mars will be harder than colonizing it ?
2) how are we going to move people there from mars to earth ?
3) how long do we need to get from mars to earth?
4) once all human get there how time flows differently in mars than earth

please put a simple introduction to our option
then speak with research about the 4 question

if you have any question refer to the file i uploaded