Which of these statements is true about the oxygen revolution? . a. cyanobacteria were the first organisms to introduce oxygen into the atmosphere.. b. protocells were the first organisms to produce oxygen in water, which then escaped into the atmosphere.. c. cyanobacteria were the first organisms to produce oxygen in water, which then escaped into the atmosphere.

Consider the diagram below, which represents components of the biosphere. what do the two arrows in the diagram most likely represent? a. radiation b. photosynthesis c. cellular respiration d. energy conversions will give to anyone who answers quickly

The blue particles in this image are able to cross the cell membrane through simple diffusion. how will they be transported? outside the cell inside the cell o a. the substances will move directly across the membrane from outside the cell to inside the cell. b. the substances will move through channels in the membrane proteins from outside the cell to inside the cell. o c. the substances will move through channels in the membrane proteins from inside the cell to outside the cell. o d. the substances will move directly across the membrane from inside the cell to outside the cell.

Which example best describes a reflex action? a. eating food when hungry b. coughing when the throat is irritated c. bending down to lift a heavy object d. going for a walk outside