The defence mechanism of human body is a gift

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CBSE Board Class 12 English Un-Solved Passages

Chapter – 4  Reading Comprehension IV (Discursive Passages)

Read the following passage carefully:

1. The defence mechanism of human body is a gift of nature provided to human beings. The power of our body to fight against various disease-producing agents is known as defensive mechanism. This defensive mechanism depends upon various factors which can be categorised mainly into two types common factors and special factors 2. Amongst the common factors, the most important is the health of human beings. We all know if we are having a good health, our body automatically remains protected against the diseases. For keeping good health one should have nutritious balanced diet. A balanced diet is that which contains carbohydrates, fat, proteins, vitamins in proportionate amount.

3. The skin of our body saves us against many micro-organisms producing diseases, provided that it is intact. In case there are cuts or abrasions on it, the micro-organisms penetrate the body through those cuts and abrasions and can cause diseases. Therefore, a cut or an abrasion should never be left open. In case there is no bandage, etc. available, it may be covered by a clean cloth.

4. Some bacteria are residing on and inside the human body. They are our friends and are useful for us They do not cause any disease and by their presence they do not allow disease-causing organisms to settle on those places. For example, the micro-organisms, present in human aliva secrete a chemic which does not allow diphtherin causing bacteria to grow inside the aral cavity

5. The human body secretes a variety of fluids, which are killers for disease causing microorgani For example, gastric juice (acidic in nature) secreted by our intestinal tract kills all organisms which enter our body through food.

6. There are a few automatic activities of our body known as “reflex phenomenon which protect the body against many infections. This reflex phenomenon includes sneezing, coughing and vomiting.

7. Fever is one of the most important constituents of the defensive mechanism of our body. The orgas which regulates the temperature of our body is known as hypothalamus and it is situated in the brain. When micro-organisms after entering the body release toxic products and these reach the brain through blood, the hypothalamus starts increasing the temperature of body and the person gets fever. This fever is very useful for the human body because by the increase of temperature the micro-organi which are the root cause of the problem get killed.

8. We are living in an environment which is full of bacteria. Many of these bacteria can produce serious diseases, but all of us do not suffer from such diseases. It is due to a special power present in our body to fight these diseases. A part of this special power of our body is known as innate immunity. This inherited by us. The other part of this special power is called acquired immunity. This we gain during our lifetime.

9. In a nutshell, we can say since nature has provided us with defensive mechanism to fight against a many diseases, let us maintain it and rather increase it by the way of immunization.

Source: Rakesh Singh The Tribune

A. On the basis of your understanding of the passage answer the questions given below by choosing one of the options that follow:

(i) One should have nutritious balanced diet because:

(a) it has food items of various tastes.

(b) it keeps one healthy.

(c) it is recommended by a dietician.

(d) it has all essential items.

(ii) The verb form of the word, immunity in para-8 is:

(a) immunizalion

(b) immunize

(c) immure

(d) immune

(iii) In order to check the micro-organisms penetration in the human body:

(a) we must rub insect repelling ail

(b) we must cover the whole body.

(c) we must use antiseptic solutions.

(d) we should keep cuts and abrasions covered,

(iv) Gastric juice secreted by our intestinal tract kills all extraneous organisms as:

(a) it flows very fast.

(b) it is acidic in nature.

(c) it is a natural stimulant.

(d) it prevents their multiplication.

(v) The word ‘toxic’ in para 7 means:

(a) blood poisoning

(b) harmful bacteria in planta/animals

(c) poisonous

(d) study of poisons

B. Answer the following questions briefly:

(i) Why should a cut or abrasion never be left open?

(ii) How is gastric juice helpful to our body? When is it produced?

(iii) What is defensive mechanism?

(iv) How can we increase our defensive mechanism?

(v) How can one keep good health?

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