Which kingdom within the domain eukarya is composed of organisms that are generally unicellular (single-celled) ?

Kingdom in the domain eukarya that is composed of organisms that are generally unicellular is protista. The protista are the organisms such slime molds, kelps and even red algae. These organisms does not contain any tissue and they are usually unicellular colonial or plainly unicellular.

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.