Give two examples in each case of (a) continuous, (b) discontinuous variation in human populations.
a) Continuous variation: for example, weight, height, intelligence, hair colour, skin colour, physique, blood pressure (any two).
b) Discontinuous variation: blood group, sex, eye colour (more or less), presence or absence of particular genetic diseases (e.g. albinism, haemophilia), free or attached ear lobes (any two).