What structures allow small particles to cross the cell membrane

Which best describes why nh4+ can form an ionic bond with cl-?

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Mitosis is a type of cell division that produces cells that are identical to the parent cell. meiosis is a different type of cell division that produces cells that carry have a genetic material of the parent cell. based on the information provided how do the purpose of mitosis and meiosis differ