U can not
No, unless the person who has made the adventure has for some reason put a virus in the files, which never happens anyway. Adventure maps are perfectly safe to download and are just shared worlds.
For the most part, yes. Make sure you always download from a trusted source to make sure any unwanted files are not downloaded with the map files.
You build a map, save it as a file, put it up for download on any website, and wait for the downloads to start rolling in.
No
Yes you can there are many maps u can download
One can only download Google Maps if their GPS is an "Android" i.e. a GPS bought from Google. If you have one of these then you can download Google Maps straight from "Google Mobile Maps".
Download them and if it is an adventure or parkour map place it in your saves file to play the map.Your saves file should be under %app% in the .minecraft folder.
Adventure maps are usually used in minecraft maps it allows you to not break certain blocks but you can use a certain item to break that block.
One can download free maps for their Garmin GPS system on the OpenStreetMap website. You will need a USB connector or a memory card in order to download the maps.
Yes minecraft adventure maps are downloadable for the general public for free
Nope
You can download it at playdota.com