When the reaction shown is correctly balanced, the coefficients are
Li + Br2 - LiBr

well off of my head we know that the perfume bottle is most likely opened, or broken. i can also tell it is moving at low and high concentration because it is covering the other side of the room. what we can obtain from this information is it explains why the odor can be detected at the other side of the room.

i'm assuming that the correct answer is indeed the first one/ "a"..

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.