Answer:
platinum-189 symbol is PT
From the ideal gas equation,

where n is number of moles, R is Universal gas constant, P is pressure, V is volume, and T is temperature of the gas.
The pressure and volume are inversely proportional to each other at constant temperature and number of moles.
Hence, on decreasing the pressure, the volume will increase.
As the hiker reaches a height of a mountain, the pressure would decrease which results in the reestablishment of equilibrium between gas molecules thus resulting in pushing of bag outwards.
Hence, the bag will expand as the hiker reaches the top of the mountain.
Answer:
Volume is the amount of space taken up an object.
Answer:
Energy is moved from areas of surplus to those of deficit, with warm currents transporting warm water polewards and cold currents taking colder water to lower latitudes. It holds onto this heat for longer than the land does and the ocean currents move this heat around, from the tropics to higher latitudes.