Which of the following elements is the most reactive? beryllium calcium magnesium barium

How do chloroplasts set plants apart from other living things

20 points and brainlist 1. london has suffered from terrible air pollution for at least seven centuries. why is the city so prone to its famous “london fog? ” what did london do to get rid of its air pollution? 2. why does air pollution cause problems in developing nations more than in developed ones?

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks