What do you mean by:
$(a)$ Blue revolution?
$(b)$ Yellow revolution?

Which one of the following nutrients is not available in fertilizers?

Differentiate between mixed cropping,intercropping,and crop rotation.

State one importance of photoperiod in agriculture.

Name the type of nutrient that we get from mustard seeds and linseed.

Balwinder was a small farmer. As his field was rain-fed,he could not take the risk of growing specialized crops. He used to mix the seeds of two crops and sow them in the field. Kaku,his son who passed class $IX$,suggested growing two or more crops simultaneously in a definite pattern. Balwinder followed this,and the productivity per unit area increased.
$(i)$ Name the cropping pattern which Balwinder used earlier and the one suggested by Kaku.
$(ii)$ Write two advantages of practicing the pattern suggested by Kaku.
$(iii)$ Write two values displayed by Kaku.