The principal involved in crop production include the following:
I. controlling of diseases, weed and pests,
II. maintaining the quality of agricultural produce,
III. conserving and preserving of natural resources,
IV. controlling soil erosion.
A. I and II only
B. III and IV only
C. I, II and III only
D. I, II,III and IV
E. II,III and IV
Correct Answer:
Option D – I, II,III and IV