Discuss the role of hybridisation in crop improvement.

Suhasini's uncle was advised by his doctor to have an ultrasound scan of his abdomen. Her uncle did not know much about the details and significance of this test. He also felt that it was too expensive and thought of postponing it. When Suhasini learnt about her uncle's problems,she immediately decided to do something about it. She took the help of her family,friends and neighbours and arranged for the cost of the test. She also told her uncle that an ultrasound scan of his abdomen would enable the doctors to know of the condition of his kidneys without causing any (test related) harm to him. This test was expensive because of its set-up that needed an expensive apparatus.
Her uncle was convinced and had the required ultrasound scan of his abdomen done. The resulting information greatly helped his doctor to treat him well.
$(a)$ What according to you,are the values displayed by Suhasini and her family,friends and neighbours to help her uncle?
$(b)$ What type of wave is used in an ultrasound scan?

Discuss why pesticides are used in very accurate concentration and in a very appropriate manner.

Which of the following is raised as food for the livestock?

Find out the correct sentence about manure:
$(i)$ Manure contains large quantities of organic matter and small quantities of nutrients.
$(ii)$ It increases the water holding capacity of sandy soil.
$(iii)$ It helps in draining out of excess of water from clayey soil.
$(iv)$ Its excessive use pollutes environment because it is made of animal excretory waste.

Differentiate between manures and fertilizers.