【单选题】Seen in a microscope, the two most dramatic events in the cell cycle are when the nucleus divides, a process called mitosis, and when the cell itself then splits in two, a process called cytokinesis. ...
【判断题】Though both hydrogen atom, H, and helium atom, He, have 1s electron configurations in ground states, their average distances of electron(s) apart from the nucleus are not equal.