Sam’s teacher is trying to model the day/night cycle on earth. one student holds a large yellow ball to represent the sun. another student holds a smaller brown ball to represent earth. how should the balls be moved to model the day/night cycle on earth?

You are given an electron micrograph of a bacterial cell. in the micrograph you can clearly see three thin layers of different densities surrounding the cell. based on the micrograph, you can infer that this cell is and would appear after application of the gram stain procedure. gram-negative / pink gram-positive / purple gram-positive / pink gram-negative / purple