What are Rabi and Kharif crops? Give two examples each.

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?

Poultry farming is undertaken to raise which of the following?
$(i)$ Egg production
$(ii)$ Feather production
$(iii)$ Chicken meat
$(iv)$ Milk production

Freshwater resources include canals,ponds,reservoirs and rivers.

Which one of the following fish variety is a surface feeder?

An Italian bee variety $A. mellifera$ has been introduced in India for honey production. Write about its merits over other varieties.