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Figure shows the two crop fields [Plots A and B] have been treated by manures and chemical fertilizers respectively, keeping other environmental factors same. Observe the graph and answer the following questions. (i) Why does plot B show sudden increase and then gradual decrease in yield? (ii) Why is the highest peak in plot A graph slightly delayed? (iii) What is the reason for the different pattern of the two graphs?

i) With addition of chemical fertilizer there is sudden increase in yield due to release of nutrients N,P,K etc in high quantity. The gradual... View Article

John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling on her neck. She visited the doctor who started medication for her. After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?

The swelling on the neck of Radha may have been because of goiter, a condition of the thyroid gland during which the gland produces insufficient... View Article

Read the following statements and write the appropriate term against each statement. A. I control the functions of a cell. Who am I? ………………. B. I am like a policeman. I do not allow anything and everything to get in and out of the cell. Who am I? ………………. C. I transfer characters from parents to offsprings. Who am I? ……………….

A. I control the function of a cell. I am the nucleus The nucleus is a double-membraned organelle that contains the genetic material and other... View Article

Which of the following statement(s) is (are) true about respiration? (i) During inhalation, ribs move inward and diaphragm is raised (ii) In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from the blood into the alveolar air (iii) Haemoglobin has a greater affinity for carbon dioxide than oxygen (iv) Alveoli increase surface area for exchange of gases (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (d) (ii) and (iv)

(d) (ii) and (iv) Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. Inhaled oxygen moves... View Article