Study the population growth curves in the graph given below and answer the questions that follow:

(i) Identify the growth curves ‘a’ and ‘b’.
(ii) Which one of them is considered a more realistic one and why?
(iii) If dN/dt = rN(K-N/K) is the equation of the logistic growth curve, what does K stand for?
(iv) What is symbolised by N?