Fill in the blanks:
$(i)$ At absolute zero,the volume of an ideal gas is ...... .
$(ii)$ With an increase in temperature,the pressure of a gas ...... .
$(iii)$ All molecular motion will stop at ...... .
$(iv)$ Due to ...... at higher altitudes from the surface of the Earth,the air becomes cooler.

(N/A) $(i)$ According to Charles's Law,$V \propto T$. As $T$ approaches $0 \ K$ (absolute zero),the volume $V$ approaches $0$.
$(ii)$ According to Gay-Lussac's Law,$P \propto T$ for a fixed volume. Therefore,as temperature increases,the pressure of the gas increases.
$(iii)$ Absolute zero temperature ($0 \ K$ or $-273.15 \ ^\circ C$) is defined as the temperature at which all thermal molecular motion ceases.
$(iv)$ As altitude increases,the atmospheric pressure decreases. The air expands and does work against the surroundings,leading to a decrease in internal energy and temperature,a process known as adiabatic cooling.