Q27 of 30 Page 1

Write the correct sequence of steps followed during journey of oxygen rich blood from lungs to various organs of human body.

(b) What happens when the system of blood vessels develop a leak?


(a) The sequence of oxygen rich blood flow from the lungs is as follows

•oxygen rich blood leaves lungs via pulmonary vein


•left Atrium receives pulmonary aorta


•blood flows from the left atrium to the left ventricle


•from left ventricle blood gets pumped to the aorta which branches to different major organs


(b) When a system of blood vessels develop a leak


•the damaged cells attracts platelets and phagocytes to the region


•phagocytes start to leak out looking for possible pathogens and digesting them


•platelets start to clump the leak and close the blood vessels to prevent blood leakage


•fibrin fibers form the clot which adds to closure of the leak


•tissue repair starts


More from this chapter

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25

(a) Compare soaps and detergents on the basis of their composition and cleansing action in hard water.

(b) What happens when ethanol is treated with sodium metal? State about the behaviour of ethanol in this reaction.


(c) Draw the structure of cyclohexane.


(d) Name the following compound



26

A metal ‘M’ is stored under kerosene. It vigorously catches fire, if a small piece of this metal is kept open in air. Dissolution of this metal in eater release great amount of energy and the metal catches fire. The solution so formed turns red litmus blue.

(a) Name the metal ‘M’


(b) write formula of the compound formed when this metal is exposed to air.


(c) Why is metal ‘M’ stored under kerosene?


(d) If oxide of this metal is treated with hydrochloric acid, what would be the products?


(e) Write balanced equations for:


(i) Reaction of ‘M’ with air.


(ii) Reaction of ‘M’ with water.


(iii) Reaction of metal oxide with hydrochloric acid.


OR


(a) Write electro dot structures of Ca (At. No. 20) and O (At. No. 8).


(b) Show the formation of calcium oxide by transfer of electrons.


(c) Name the ions present in the compound.


(d) List four important characteristics of this compound.


 28

(a) Suggest any two categories of contraceptive methods to control the size of human population which is essential for the prosperity of a country. Also explain about each method briefly.

(b) Name two bacterial and two viral infections each that can get sexually transmitted.


(c) List two advantages of using condom during sexual acct.


OR


(a) Draw a diagram to show spore formation in Rhizopus.


(b) With the help of an example differentiate between the process of Budding and Fragmentation.


(c) Why is vegetative propagation practiced for growing some type of plants?


 29

(a) A security mirror used in a big showroom has radius of curvature 5 m. If a customer is standing at a distance of 20, from the cash counter, find the position, nature and size of the image formed in the security mirror.

(b) Neha visited a dentist in his clinic. She observed that the dentist was holding an instrument fitted with a mirror. State the nature of this mirror and reason for its use in the instrument used by dentist.


OR


Rishi went to a palmist to show his palm. The palmist used a special lens for this purpose.


(i) State the nature of the lens and reasons for its use.


(ii) Where should the palmist place/hold the lens so as to have a real and magnified image of an object?


(iii) If the focal length of this lens is 10 cm, the lens is held at a distance of 5 cm from the palm, use lens formula to fine the position and size of the image.