Bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. they use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. these bacteria are :
a. chemoheterotrophs
b. photoautotrophs
c. chemoautotrophs
d. photoheterotrophs
e. none of the above

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

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.

c should be the answer