Please help do not know the answer

In this experiment you were asked to present three possible mechanisms. describe those mechanisms here and include drawings of those mechanisms. how will the bromination of trans-cinnamic acid and trans-stilbene allow you to distinguish between the three possibilities? what would you expect to find in your data in each scenario?

Of seawater increases with decrease in the temperature. therefore, the cold water sinks to the deeper layers at the bottom

Several billion years ago which gas was the least prevailant in the atmosphere