Whixh abiotic factor is necessary for animals to survive in an aquatic ecosystem? a. dissolved o2 b. light c. low salinity d. algal blooms e. dissolved co2

a. dissolved O2

Oxygen is a vital gas that is required by all living organisms for their respiration and cellular metabolism. It is an important abiotic (non-living factor)   . The oxygen is abundantly present in the atmosphere which is easily respired by the land plants and animals but in the aquatic ecosystem the oxygen is dissolved from the atmosphere.  The oxygen should be replenished as it is used by the aquatic plants and animals in the water.

answer; i believe the correct answer is (a)0

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.