Breathing is an essential part of the works of the body. If you go a long time without breathing, you’ll die. The reason why you can go a long time without eating is because your body stores the fat to keep you going. Breathing is kind of the building block of the body.
I believe it would be manual labor. During the Industrial Age of Employment, most people would have to do repetitive jobs, or manual labor. Design, engineer, and knowledge broker were not common during this time.
Cellulose is a straight chain polysaccharide which is made up of glucose molecules that are joined together by beta 1,4 glycosidic bonds. Cellulose is the principal structural material of plants and plants use it to build strong structures. For instances, the rigid cell wall of plant cells is made up of cellulose.
Thus, the correct option is D.
