STATE TRUE OR FALSE a) natural gas has a characteristic odour
b) natural gas is heavier than air
c) synthetic fibres, polymers, dyes are synthesized from petrochemicals
d) we should use convential bulb's instead if LED'S
e) emission of CO2 gas during burning of fossil fuels burn global warming

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.

i'm pretty sure its b i might be wrong though!