If oxygen is not present, glycolysis would be followed by fermentation
ECM is the extracellular matrix, or the set of extracellular molecules secreted by cells with the purpose to support surrounding cells. In plants the cell wall is the ECM and in mammals ECM can be in the form of fibrils and may constitute a significant portion of the bulk of the organism and it also referred as connective tissue.
D. controlled cell suicide
The generalization that all organisms are composed of cells was established through multiple observations in various kinds of animals and plants. A controlled experiment of finding cells in all the kinds of living organisms is not possible or is infeasible as it will require prior knowledge of all the kinds of organisms inhabiting Earth and the effort to catch and bring them in the controlled environment of the lab for testing.
