State how barseem,oats,or sudan grass are used by farmers.

Two friends,Girish and Neeraj,were discussing Newton's third law. They were perplexed about how action and reaction are equal and opposite. They could not think of an experiment by which they could ascertain this fact. Pushkar,who was their friend,told them that he would set up an experiment to prove this to them. By performing an experiment,Pushkar demonstrated the law.
$(a)$ Can you think of an experiment by which you can demonstrate this law?
$(b)$ What values do you think Pushkar has?

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

$A$ teacher mentioned organisms that enrich the soil with nutrients. Rahila was curious to know more about them. She searched the internet and learned about $Rhizobium$ bacteria and cyanobacteria.
$(i)$ What are bio-fertilizers?
$(ii)$ Explain how any one of the organisms mentioned above enriches the soil with nutrients.
$(iii)$ Why was Rahila curious to get more information?

$A$ farmer wanted to invest some money in fish farming. But he did not get right guidance.
$(a)$ How can you guide him for a profitable business in spite of limitations of fish farming?
$(b)$ What is the limitation of fish farming?

Mention any two abiotic factors that affect crop production.