Why does air at 75% relative humidity and 30°c make your skin feel stickier than air at 75% relative humidity at 10°c?

warm air rises while cold air falls.
the warmer air contains less water vapor per unit of volume.
the warmer air contains more water vapor per unit of volume.
moist air has lower density than dry air does.

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons