Apyroclastic flow typically occurs during a quiet eruption.

That is False. A pyroclastic Flow typically occurs during a explosive erupiton. No Pyroclastic flows are a product of explosive eruptions. Pyroclastic flow typically occurs during a violent eruption. No. A "quiet" eruption will produce lava flows. Pyroclastic flows generally. Result from explosive eruptions. Yes. A pyroclastic flow is essentially a sort of avalanche of hot ash, rock, and gas ejected by an explosive volcanic eruption. The answer is Explosive . It is explosive because during a explosive eruption there are clouds of ash, gas , and rock , and with a pyroclastic flow there is dust and ash . there for the answer must be explosive . Explosive eruptions That depends on the sense in which you mean silent. Pyroclastic flows are generate by explosive rather than "quiet" eruptions. However, no sound escapes the flows themselves. Their unusual acoustic properties ensure that the sound they produce remains trapped inside.

True as the lakes are a marine body. also there's no difference in lake and ocean except for the size.

Air pollution: “combustion results in gases such as nitrogen oxides, nitrogen dioxide and particulates. the main causes of air pollution include transport, domestic combustion and industrial processes. pollutants from these sources can cause problems in the immediate vicinity and a distance away.”