Kidneys are a filter system. The main job of the kidneys is to remove waste from the blood and return the cleaned blood back to the body. Each minute about one litre of blood ï­ one-fifth of all the blood pumped by the heart - enters the kidneys through the renal arteries.
The volume of helium in the balloon has been estimated as being able to lift a total load, including the balloon material and the structure beneath it, of 65 pounds (29 kg) at sea level and 48 pounds (22 kg) at 8,000 feet (2,400 m).
Thus even the air inside would be heavier than the equivalent mass of uncompressed air outside. Therefore it also makes sense to use a material that does not stretch. In order to make the balloon float, we must fill it with a gas that is not as dense as the air that surrounds it. Helium is ideal because the molecules are spread out much more than the molecules in the surrounding air -- and is therefore lighter (fewer molecules means less weight for a given mass of gas). Moreover, the material used in helium-filled balloons (party balloons) is wafer-thin and extremely light.