Why is organic matter important for crop production?

$(i)$ State three ways by which pests attack plants.
$(ii)$ Name the chemicals used to control pests.
$(iii)$ Explain why excessive use of such chemicals should be avoided.

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

Gautam visited a fair along with his classmates. There he found that a hawker was selling balloons filled with helium gas. His teacher told the students that the balloons will rise in the sky and then stop after some distance. Gautam questioned his teacher as to why the balloons would stop. He started arguing with his teacher that the balloons would rise indefinitely. His teacher got irritated with him. Just then,Gautam's friend Avdesh took him aside and explained to him that the teacher was correct. The explanation given by Avdesh satisfied Gautam.
$(a)$ Why will the balloon stop after rising to a certain height?
$(b)$ What values are shown by Avdesh and Gautam?

Cattle husbandry is done for the following purposes:
$(i)$ Milk production
$(ii)$ Agricultural work
$(iii)$ Meat production
$(iv)$ Egg production

Name the two vitamins which are added in the poultry feed.