What causes earth's crust to crumble and fold

Which type of respiration takes place when there is no oxygen present? a. anaerobic b. mitochondrial c. cellular d. aerobica. anaerobic

19. a cell is viewed under a microscope and is found to have two nuclear envelopes and spindles that appear to be breaking apart. which phase of mitosis is the cell most likely in? a. metaphase b. prophase c. telophase d. anaphase

What materials must dams have to produce electricity, and what must occur?