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Q Is there a one-eyed fish called a Cyclops?

No, but there is a small crustacean with one eye called a Cyclops. They are small (rarely more than half an inch long), can be green, orange, blue or red, have a red or black eye, and swim in salt or fresh water depending on the species. This group of crustaceans is called the copepods so Cyclops are a type of copepod.

Q Boiling water kills germs and bacteria, but what does freezing water do to them?

It depends on the bacteria. If you put samples of E. coli or salmonella into ice they will stop growing, but they will survive maybe a month or more. Other species are more delicate. For example, campylobacter, which causes food poisoning, grows at 37C to 42C. The bacteria generally die below room temperature, although they can be stored alive at -80C if they are frozen very fast under the right conditions. There is a group of microbes called psychrophiles which thrive in freezing environments, for example Antarctic sea ice (ocean water that is frozen for much of the year). But apart from specially adapted organisms, freezing conditions generally stop the growth of bacteria, although it cannot be guaranteed to kill them.

Q What is the highest altitude any aeroplane can fly at?

Commercial aircraft fly at about 30,000 feet (9,144 metres) but military aircraft can fly at up to 60,000 feet. At altitudes above 60,000 feet the air becomes so thin that the weight of the plane can no longer be supported.

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