(2) brown bottles stops the passage of light through it Explanation: Silver Nitrate is stored in dark bottles in a laboratory to prevent chemical reactions as it is sensitive to light. It reacts to light to produce silver metal.
In upper layer of atmosphere ozone is formed by - (1) the action of ultraviolet rays on oxygen (2) the combination of oxygen molecules (3) subjecting oxygen to high pressure (4) the action of nitrogen on oxygen in atmosphere