Identify two crops from the following which provide us carbohydrates for energy requirement:
Black gram,Wheat,Lentil,Rice

What is the advantage of green manure?

Based on the kind of biological material used,what are the two kinds of manures? How are they prepared?

$(i)$ Name the three varieties of pesticides used.
$(ii)$ Write the problems related to the excess use of pesticides.

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

Rajan and his family members were going to Dalhousie in a car to enjoy their weekly holidays. While on the way,it started raining. During the journey,Rajan observed that when another vehicle or bus passed them and honked,the intensity of the sound produced was higher than it would be in an area without rain.
$(a)$ What,according to you,is the reason behind the increase in the intensity of sound during rain?
$(b)$ What value do you attribute to Rajan's observation?