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Ah yes, the question which haunted my years of study, particularly during GCSE and A Levels.

At this stage, many exams are ‘open book’ - that is, you can take either a blank or highlighte...

In chemistry if a substance is oxidised it loses electrons in a reaction.

If a substance is reduced it gains electrons in a reaction.

A reaction that has both oxidation and ...

Sometimes microorganisms are able to make it past the body's external defences (i.e. the skin) the body's immune system must defend the body.

White blood cells are really important in the...