It depends on your specific back issues, as well as your own body elements, such as weight, physique, and genetic inheritances. Air beds help some people, while others are not helped; talk to your doctor about your specific problems before you go and spend a bunch of money on one of these mattresses.
A garrison,Artillery crew or air support.
No, the m50 mask is not the most effective in confined spaces where there is not enough oxygen in the air to breathe to support life.
A combined air arms force including recon, ground support, bombers with fighter support and recon to provide an after action report. In modern terms, recon is done by sattellite, fighters also provide fire suppression and ground support and can provide a bombing capability, so a single flight of modern aircraft can constitute an air armada.
Atoms of many gases exist in space, but they are not concentrated enough to provide a breathable atmosphere (air).
Because in atmospheric layers above the troposphere, there isn't enough oxygen to support the kind of energy consumption that birds require. Also, because the air isn't thick enough to provide sufficient lift at high altitude.
you have to jump high enough to do a 360 in the air
Orchids have air roots to absorb moisture and nutrients from the air, as well as to provide stability and support for the plant.
Orchids grow air roots to absorb moisture and nutrients from the air, as well as to provide additional support for the plant.
To provide an electrical spark hot enough to ignite the air/fuel mixture
It is used to provide aerial (for wars and non-war purposes) and humanitarian support around the world.
water is a liquid and the air is a lot less dense liquid. so the bouancies of the two are extremly diffrent. the shape of the duck that's above water weights enough to equal the bauncy of the water. the weight of the duck in air is more then the bouncy of the air
Objects less dense than air can float on air of that density. Air passing over objects (wings, kites, etc.) can provide lift and support the object. Air moving upwards at a speed equivalent to the terminal velocity of the object in the air stream will support the object. Solid air (frozen at -299oC if you don't care about the Helium or -270oC if you do) will support objects like any other solid.