A It is possible for a densely populated country to be under-populated if it has insufficient labour to make the most effective use of its other factors
B The quantity of labour, which combines with other factors, gives the minimum output, is known as optimum population
C The quantity of labour, which combined with the other factors, gives the maximum output, is known as optimum population
D The test of over-population is whether it exceeds the optimum
E It is possible for a thinly populated country to be over- populated if it has a poor supply of other factors