As you climb higher the less oxygen you because higher altitudes and because atmospheric pressure is lower, the air molecules and hence the O2 is less concentrated per unit volume.
That depends on which country and which mountains you are thinking of.
ya because u need air to breathe and air is thin the higher you go up in the air
The entertainment in the cascade mountains is just hiking and the scenery.
Hiking and camping.
There are a few bits of equipment which are vital when hiking in the Adirondack Mountains. Books and maps are necessary as are weather resistant clothes and suitable walking boots.
Yes . It is hiking and stuff
there are many hikers hiking up mountains
you can go camping, hiking, swimming, biking, and rock climbing.
Hiking boots are good, athletic shoes.
Joe Kelsey has written: 'Climbing and hiking in the Wind River Mountains' -- subject(s): Guidebooks, Hiking, Mountaineering
Colorado River in the Grand Canyon
The park contains 850 miles of hiking trails.