Biomass is plant or animal material used as fuel to produce electricity or heat. Therefore i think the answer is plants!
The organisms in a pond and the physical factors <span>influencing them best describe "an ecosystem" since this is a self-contained environment will multiple organisms. </span>
The three main stages of cellular respiration (aerobic) would include Glycolysis in the cytoplasm, the Kreb's Cycle in the Mitochondrial Matrix and the Electron Transport Chain in the Mitochondrial Membrane.
The connective tissue is among the four major classes of the tissue. It is the most widely distributed and the most abundant class of the tissues. However, the type of tissue in every organ varies. Composed of cells, fibers and matrix, this type of tissue is different in different organs of the body.
The variability in it's type is provided by the difference in the degree of the order of the cells, fibers, and the matrix. This variability contributes to the diversity of this tissue.
Hence, the blank can be filled with 'diversity'.