A 2. Which of the following are features that help scientists classify annelids into their respective classes? O presence of setae and tentacles presence of setae and parapodia presence of setae and septa presence of coelom and parapodia

presence of setae and parapodia

Explanation:

Annelids are groups of organisms under the phylum "Annelida". They are organisms that possess the following characteristics or features: setae, parapodia, coelom, tentacles etc. However, via the possession of not of the setae and parapodia, annelids have been classified into four major classes viz: Polychaeta, Oligochaeta, Hiradinea and Archiannelida, on the basis of their setae and parapodia mainly.

- Polychaeta: possess numerous setae and parapodia

- Oligochaeta: few setae, no parapodia

- Hiradinea: No setae, no parapodia

- Archiannelida: No setae, no parapodia

Hence, the presence of setae and parapodia will enable the scientists classify annelids into their respective classes.

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.