What are the characteristics of human needs according to the text?
They originate from physiological or spiritual demands that humans must satisfy to make life possible.
They are limited in number.
They are concurrent and selective.
They are not substitutable.
They tend to become fixed.
They vary in intensity.
They are classified as traditional and modern.

a) I, II, III, V and VI are correct.
b) II, III, IV, V and VI are correct.
c) I, III, IV, V and VI are correct.
d) All are correct.