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CLASS 9 BIOLOGY MODEL QUESTIONS AND ANSWERS

CLASS 9 BIOLOGY

  1. Complete the table.
Excretory organ Function
—(a)—- Production of urea
Skin —(b)—-

 

  1. What are  lenticels? What is their importance?
  2. Find the missing item in the second pair on the basis of the relationship between the items in the first pair.

Valves are absent: Capillary

Valves are present  : …………………………

  1. Complete the statement.

—– are the basic structural and functional units of kidneys.

  1. Identify the correct statement related to pulmonary circulation.

(a) From the left ventricle to the right atrium.

(b) From the right ventricle to the left atrium.

(c) From the left atrium to the right ventricle.

(d) From the left ventricle to the right ventricle.

  1. Find the odd one in the group. Write the common feature of the others.

Pepsin, Trypsin, Mucus, Hydrochloric acid.

  1. Given below is the effect of a lung disorder.
Alveoli rupture due to the loss of elasticity, by the deposition of toxic substances in tobacco.

 

(a)Identify the disorder.

(b)How does it affect the lungs?

  1. Make appropriate pairs using the items given in the box.
Malpighian tubule, Earthworm, Insects, Contractile vacuole, Kidney, Nephridia, Fish, Amoeba
  1. Rearrange the items in columns B and C so that they match with the items in column A.
A B C
(i)  

Nephritis

(a) Deposition of crystals of calcium salts in kidney. (1) Anaemia, Loss of body weight, Dizziness, Suffocation
(ii) 

Uremia

(b)Inflammation of the kidneys due to infection or toxicity. (2) Pain in the lower abdomen, Blockage of urine, Dizziness, Vomiting
(c) Different types of kidney diseases, Diabetes. (3) Turbid and dark coloured urine, Oedema on face and ankle.

 

  1. Differentiate between tidal volume and vital capacity.
  2. What is the role of transpiration in transporting water absorbed by roots into leaves?
  3. ‘Plants have a major role in the mitigation of natural disasters’. Substantiate this statement.
  4. Complete the flowchart showing the process of swallowing of food.

Tongue compresses food into balls with the help of the palate. (a)(b)(c)Food into the stomach.

  1. Write the roles played by the following in the process of excretion in plants.

(a) Hydathodes (b) Abscission of leaves

(c) Formation of heartwood.

  1. Drinking is a bad habit that is to be avoided.  Write your response  to this statement.

ANSWERS 

  1. (a) Liver (b) Expels water and salts.
  2. Lenticels are small pores seen on the surface of stem and roots. Exchange of gases takes place in stem and roots through lenticels.
  3. Vein; Blood vessels and their peculiarities.
  4. Nephrons
  5. (b) From the right ventricle to the left atrium.
  6. Trypsin; the others are components of the gastric juice.
  7. (a)Emphysema

(b) It reduces the respiratory surface and vital capacity.

  1. Earthworm- Nephridia

Insects- Malpighian tubules

Fish – Kidney

Amoeba- Contractile vacuole

  1. (i) – b-3, (ii) – c-1
  2. Tidal volume is the volume of air we breathe in and out during normal breathing. In humans, tidal volume  is about 500 ml.

Vital capacity is the volume of air that can be breathed out by forceful expiration after forceful inspiration.

  1. During transpiration, water is lost from the intercellular spaces of leaves through stomata. This reduces the pressure in the cells of leaves. In order to compensate this pressure difference, water enters these cells from adjacent cells through osmosis. The transpiration pull that develops due to transpiration helps to carry water to the leaves.
  2. Mangrove forests help in controlling tsumani to some extent. Bamboo forests, reed, vetiver, lemon grass etc protect river banks from collapsing during floods. Trees and bushes in mountains and hills prevent soil erosion and landslide.
  3. (a) Uvula closes the nasal cavity that opens to the pharynx.

 (b) Trachea rises up and is closed by the epiglottis.

 (c) The posterior part of the tongue allows food to move over the epiglottis into the oesophagus.

  1. (a) Hydathodes : In certain grasses and shrubs, excess water is expelled through small pores at the tip of leves called hydathodes.

(b) Abscission of leaves: When leaves are about to  fall, plants absorb all useful materials from them. Falling leaves contain mostly wastes.

(c) Formation of heartwood: Some waste materials accumulate in the older xylem vessels present at the centre of the tree trunk. This region is called heartwood.

  1. Contact with poisonous substances destroy liver cells. But, unlike other organs, liver has the ability to regenerate its damaged cells. Even then, if the destruction of liver cells becomes higher than its regenerative power, it will lead to the complete damage of liver. This happens in a person who  uses alcohol. So it is necessary to avoid the use of alcohol.
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