Respiration is the process by which organisms convert food into chemical energy and requires oxygen.
The carbon containing molecule found in the atmosphere that is often released by respiration is carbon dioxide. Carbon dioxide from body cells is exchanged for oxygen from blood.
Plant cells are surrounded by a tough extracellular matrix in the form of a cell wall, which is responsible for many of the unique features of a plant's life style. The cell wall is composed of a network of cellulose microfibrils and cross-linking glycans embedded in a highly cross-linked matrix of pectin polysaccharides. In secondary cell walls, lignin may be deposited. A cortical array of microtubules can determine the orientation of newly deposited cellulose microfibrils, which in turn determines directional cell expansion and therefore the final shape of the cell and, ultimately, of the plant as a whole.
Endocrine system is the answer
I believe it is A.Autotrophs because carnivores gather their energy from eating meat and herbivores gather their energy from plants
