CAIE A Level Biology 9700 · Immunity
A novel virus, Pneumoviridae X, infects epithelial cells of the human respiratory tract. During the primary immune response to this virus, both T-helper and T-killer cells become activated.
Compare the roles of T-helper cells and T-killer cells in this immune response.
7 marks, so the mark scheme is looking for about 7 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
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