The rule for controls is that
a. controls are only necessary if you're not doing an experiment
b. everything should remain the same between experimental groups
c. there should be only one independent variable and one dependent variable
d. the only change we make between experimental groups is to the independent variable

velocity and height

idk why hjggjhjkhj

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.