Using one or more complete sentences, state one specific change that occurs in the gas composition of the blood as the blood moves from
structure 6 to structure 3. Specify whether the change is an increase or a
decrease in composition. *

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.

b is the answer and if you need further with anything message me