CBSE Solutions for Class 10 English

જવાબ : The animals that feed only on plants are called herbivores.
The animals that feed only on flesh are called carnivores.

જવાબ : The factors which affect photosynthesis, are light, water, temperature, humidity, age of the leaf and carbon dioxide.

જવાબ : The two stages in photosynthesis are
(i) Light reaction and
(ii) Dark reaction.

જવાબ : Chlorophyll is the pigment, which can absorb solar energy.

જવાબ : salivary amylase

જવાબ : proteins, lipase

જવાબ : villi

જવાબ : lactic acid, anaerobic

જવાબ : residual volume

જવાબ : valves

જવાબ : veins

જવાબ : two, three

જવાબ : capillary

જવાબ : tracheids, vessels

જવાબ : transpiration pull

જવાબ : Sucrose

જવાબ : Urine

જવાબ : reabsorbs

જવાબ : Dialysis

જવાબ : transpiration

જવાબ : Aerobic

જવાબ : Vacuoles

જવાબ : phloem

જવાબ : platelet

જવાબ : air-passage does not collapse

જવાબ : mitochondria

જવાબ : sphincter

જવાબ : Small intestine

જવાબ : cytoplasm

જવાબ : Small intestine

જવાબ : The name given to the process of using the absorbed food for producing energy is assimilation.

જવાબ : Digestion begins from the mouth.

જવાબ : The compensation point is the amount of light on the light curve where the rate of photosynthesis exactly matches the rate of respiration.
At this point, the uptake of CO₂ through photosynthetic pathways is exactly matched to the respiratory release of carbon dioxide, and the uptake of O₂ by respiration is exactly matched to the photosynthetic release of oxygen. This point is reached during early mornings and late evenings.

જવાબ : Chemotrophs are organisms, which do not require light. They manufacture their food from inorganic substances in the presence of energy derived from the oxidation of simple inorganic compounds of iron, sulphur, etc.
e.g. bacterium Nitrosomonas.

જવાબ : The living organisms that cannot make their own food called heterotrophs.

જવાબ : The phenomenon of breaking down of water in the illuminated chloroplast is known as photolysis.

જવાબ : Epiglottis prevents the food from entering into the trachea.

જવાબ : (i) Prawns take in oxygen that is dissolved in water.
(ii) Rat takes in oxygen from the atmosphere.

જવાબ : The respiratory organs of
(i) fish – gills
(ii) mosquito – tracheoles
(iii) earthworm – skin
(iv) dog – lungs.

જવાબ : The respiration in plants differ from respiration in animals in two respects, they are
(i) There is minimal transport of gases from one part of the plant to another, unlike the animals. (ii) Plant respiration occurs at a much slower rate than animal respiration.

જવાબ : (i) Stomata are tiny apertures found on the surface of the leaf, which regulate the exchange of respiratory gases and transpiration.
(ii) Lenticels are the raised pores in the woody plants that allow the exchange of gases between the atmosphere and the internal tissues.

જવાબ : Root hair is the part of the root which is involved in exchange of respiratory gases.

જવાબ : In aerobic respiration more energy is released.

જવાબ : Respiration is a complex process, which includes breathing, the mechanism of exchange of gases,oxygen and carbon dioxide and oxidation of digested food occurring in the cells in order to release energy. The main outcome of respiration is the release of energy through oxidation of simple food molecules such as glucose.

જવાબ : Saprophytic nutrition is the mode of nutrition that is seen in fungi.

જવાબ : Nutrition is the process of intake, as well as utilization of nutrients by an organism. The different modes of nutrition are saprophytic nutrition, parasitic nutrition and holozoic nutrition.

જવાબ : Breathing is a process by which organisms inhale oxygen. The inhaled oxygen gets diffused into the blood and the carbon dioxide from the blood diffuses back into the alveoli from where it is exhaled.

જવાબ : The liver secretes bile, which contains bile pigments and bile salts. The bile secreted by the liver cells is normally stored in the gall bladder, until needed in the duodenum. Pancreas lie parallel to and beneath the stomach. It is a large gland, which secretes digestive enzymes as well as the hormones, insulin and glucagons. Both bile and pancreatic juice enter duodenum through a common duct. Bile emulsifies fat present in the food. Pancreatic juice contains trypsin, for digesting proteins and pancreatic amylase for the breakdown of starch.

જવાબ : The parts of digestive system of a grasshopper are pharynx, salivary glands, hepatic caeca, malpighian tubules, ileum, colon, rectum and anus.

જવાબ : Amoeba engulfs its food by extending pseudopodia. This process is known as Phagocytes.

જવાબ : Animals are complex multicellular organisms where there is specialisation for almost all functions like intake of food, exchange of gases and elimination of body wastes. However, every cell of the body requires nutrients and oxygen. It also eliminates CCfy and wastes. Therefore, each and every cell has to be connected to a transportation system for receiving and giving out materials. The transportation system is blood circulatory system in vertebrates. It picks up nutrients from digestive tract, oxygen from respiratory system and hormones from endocrine glands. The same are supplied to cells. Similarly, it takes carbon dioxide to respiratory surface and excretory products to kidneys for removal from’ the body

જવાબ : Single celled organisms are in direct contact with the environment so that diffusion is helpful to them in exchange of gases, removal of wastes and even meeting their requirement of food. However, in most * multicellular organisms, the body is covered by dead cells. Cell to cell diffusion is unable to meet the requirement of all body cells. For example, in humans cell to cell diffusion will take three .years to send oxygen from lungs to toes. Multicellular organisms have developed specialised structures for performing different functions, e.g., digestive tract, respiratory surface, excretory organs. These structures are connected to all body cells through a transport system, e.g., circulatory system in animals, xylem and phloem in plants. The transport system is quite fast to bring materials to and from the cells.

જવાબ : (a) Every living cell requires oxygen for performing cellular respiration. In unicellular organisms (e.g., Amoeba), the single cell is in direct contact with environment. Oxygen passes into it through diffusion. In simple multicellular organisms (e.g., Hydra), every cell may also get oxygen through diffusion from environment. This is not possible in complex multicellular organisms like humans. The body is covered by dead cells. The living cells are not in contact with external environment. Air containing intercellular spaces are absent. Therefore, quick diffusion cannot occur. Cell to cell diffusion is a very slow process. Passage of oxygen from lungs to toes through cell to cell diffusion will take about three years. Therefore, diffusion cannot meet the oxygen requirement of multicellular organisms like humans.
(b) Large animals have a respiratory system for meeting their oxygen requirement,

1. There is a large moist permeable membrane over a respiratory area for quick exchange of gases,
2. The respiratory surface has abundant blood supply for bringing in CO₂ and taking away O₂.
3. There is a mechanism for quick movement of fresh air over the respiratory surface and rapid disposal of foul air.

જવાબ : Glomerular filtrate contains a lot of water and useful substances while the blood passing into efferent arteriole contains a good quantity of wastes. Therefore, a long passage and hence lot of filtrate is required to correct the situation. It involves reabsorption of glucose, amino acids, ions and water in PCT and secretion of urea and other wastes from blood capillaries into urine in DCT. Urine concentration occurs in PCT, loops of Henle, DCT, collecting tubules and ducts.

જવાબ : (a) Translocation is passage of food materials in solution form in plants from the region of their supply or manufacture to the region of their use or storage.
In plants the region of manufacture of food is only foliage while food is required by the whole plant including deep root tips and top buds and flowers. Similarly regions of storage are also away. Therefore, a translocation is always required.
(b) Delivery of Translocated Substances. The major areas where translocated substances are delivered are storage regions, growing regions, ripening fruits, etc. Of course, every living cell requires the translocates.

જવાબ : (a) Bread contains starch which is acted upon by ptyalin (salivary amylase) to form sweet sugar maltose.
(b) Human beings have no enzymes and symbiotic bacteria for digestion of cellulose. Therefore, cellulose functions only as roughage in human beings. In cow the stomach contains cellulose digesting (fermenting) bacteria and protozoa that convert it into soluble and absorbable components including glucose.

જવાબ : Guard cells: Opening and closing of stomata is regulated by gain or loss of turgidity of their guard cells. During opening of stomata, guard cells withdraw K⁺ ions from surrounding epidermal cells, followed by absorption of water from them. As a result, guard cells swell up and become turgid. Their outer thin and elastic walls bend outwardly followed by outward movement of thicker inner walls. The latter creates a pore in between the two guard cells.
During closure movement of stomata, guard cells send out K⁺ ions. Water also passes out. Guard cells become flaccid. Their inner thick walls come to touch each other. The stomatal pore gets closed.

જવાબ : (a) Double circulation is the passage of same blood twice through heart, first from right side to lungs and back to left side for passage to rest of the body to be returned to right side. It consists of two components, pulmonary circulation (from heart to lungs and back) and systemic circulation (from heart to different parts of body and back). In pulmonary circulation deoxygenated blood is converted into oxygenated blood. In systemic circulation oxygenated blood is supplied to all parts of the body. It gets changed into deoxygenated form.
(b) Importance. Double circulation ensures supply of oxygenated blood to all body parts for efficient release of energy to ensure higher physical activity and thermoregulation of body. It also provides for direct passage of all deoxygenated blood to lungs for oxygenation.

જવાબ : Site of Complete Digestion. Small intestine.
Digestion. It is the conversion of complex insoluble food ingredients into simple absorbable form. Digestion is essential as complex components of food cannot pass into body cells for nourishment. Digestion occurs with the help of digestive enzymes. In simple holozoic animals, it is intracellular. In higher animals digestion is performed in a digestive tract and is, therefore, intercellular or extracellular. The digested materials are absorbed, transported and picked up by individual cells of the body for assimilation.

જવાબ : (a) Importance

1. Cooling: Evaporation of water from the aerial parts results in lowering of their temperature which will otherwise rise due to exposure to sun.
2. Concentration of Mineral:. Transpiration helps in increasing concentration of minerals present in rising water.
3. Transport: It creates a pull that helps in transport of water and minerals.

જવાબ : (a) Aerobic and anaerobic.
(b) Differences

જવાબ : (a) The process of taking in of oxygen from air in to the lungs and expulsion of carbon dioxide out of the lungs is called breathing. The rate of breathing during vigorous exercise increases by about 20 to 25 times per minute. It is because, during vigorous exercise the demand for oxygen increases. Breathing occurs involuntarily but its rate is controlled by the respiratory center of the brain.
(b) Translocation is the transport of food from the leaves to other parts of the plant and occurs in the part of the vascular tissue known as phloem.
It is essential for plants because every part of the plant needs food for obtaining energy for building its parts and maintaining its life.
(i) Sugar is synthesised in the leaves of the plant.
(ii) Hormones are synthesised at the tips of roots and stems of a plant.

જવાબ : (a) The three events that occur during the process of photosynthesis are:
(i) Absorption of light energy by the green pigment chlorophyll.
(ii) Conversion of light energy into chemical energy and the splitting of water molecule into hydrogen and oxygen.
(iii) Reduction of carbon dioxide into carbohydrate.
Role of Stomata
Stomata are tiny pores present on the surface of leaves. They are also present on the surface of young stems. Stomata are mainly engaged in the exchange of gases (entry of CO₂ and release of O₂ ) associated with photosynthesis. Plant closes the stomata when it does not need CO₂ for photosynthesis.
(b) Sunlight is essential for photosynthesis

Procedure:
(i) Place a healthy green potted plant in a dark room for 1-2 days. This is done to ensure
that the plant consumes all its reserve food and the leaves do not contain any starch.
(ii) Then, cover a portion of a leaf of this plant on both sides with two uniform pieces of black paper, fixed in position with two paper clips.
(iii) Now, expose this plant to bright light. After a few hours, remove the leaf and decolorize it with alcohol and test the presence of food (starch) with iodine solution.
Observation: It can be observed that the portion of the leaf covered with black paper does not (food),
Conclusion: This is because the food prepared by plants through the process of photosynthesis is stored as starch. Starch reacts with the iodine solution to give blue-black colour. Only those portions of the leaf that were exposed to sunlight could photosynthesise. Hence, gives blue- black colour when tested with iodine. The portion of the leaf covered with black paper did not receive sunlight. Hence, starch was not produced. Thus, it can be
concluded that the sunlight is essential for photosynthesis.

જવાબ : Unicellular organisms can absorb sufficient oxygen because of its complete contact with the atmosphere, but in multicellular organisms the rate of absorption and diffusion becomes very less because all cells are not in direct contact with the atmosphere. Multicellular organisms require greater amount of oxygen to sustain life processes which cannot be fulfilled by the process of diffusion.

જવાબ : (i) Digestive enzymes – Foods need to be broken into their small or simpler
molecules so that they can be absorbed into the bloodstream. However, the physical breakdown of food is not enough. Enzymes are hence needed for the chemical breakdown of food and speeding up the digestive process. The products of digestion can hence be small enough to be absorbed.

જવાબ : (a) In plants there are tiny pores called stomata on leaves and lenticels in stem which facilitate the exchange of gases. Carbon dioxide is taken in and oxygen given out {during photosynthesis} and vice versa during respiration.
(b) Water and minerals are transported within the plant by the Xylem vessels (mainly in an upward direction); these are part of the vascular system which also includes Phloem vessels.
Phloem transports the products of photosynthesis within the plant, to all parts like the stem, roots, fruits etc. in all directions.

જવાબ :

1. Take a healthy leaf from the potted plant.
2. Remove a part of the peel from the lower surface of the leaf. You can do this by folding the leaf over and gently pulling the peel apart using forceps. Keeps the peel in a watch glass containing water.
3. Put a few drops of safranin stain in a watch glass.
4. After 2-3 minutes take out the peel and place it on a clean glass slide.
5. Put a drop of glycerin over the peel and place a clean covers lip gently over it with the help of a needle.
6. Remove the excess stain and glycerin with the help of blotting paper.
7.  Observe the slide under magnifications of the compound microscope.

જવાબ : (a)(i) It sterilises food by killing pathogens and other microbes.
(ii) It has a pH of 2, which is perfect for entyaus such as pepsin to break down proteins as effectively as possible.
(iii) Helps emulsify food (digestion of protein and stimulates the pancreas to produce digestive enzymes and bile) and protects against harmful ‘ bacteria
(b) Breakdown of large gloubule fats into smaller fats droplets is known as emulsification.
(c) Trypsin is the enzyme secreted by the pancreas which aids in digestion of proteins.

જવાબ : These features which particularly make our lungs efficient for gas exchange.
1.Thin: the air sac walls are very thin so that gases can quickly diffuse through them. Oxygen is absorbed in to the blood and carbon dioxide is given out in to the lungs to be exhaled out.
2.Moist: the air sacs are moist with mucus so that gases can dissolve before diffusing.
3.Large surface area: the surface area for gases to diffuse through in human lungs is roughly the same as a tennis court. The alveoli help to increase the surface area for absorption of oxygen.
4.Good blood supply: the air sacs or the alveoli have a large capillary network so that large volumes of gases can be exchanged. More the flow of blood more exchange.

જવાબ : Mammals and birds are warm blooded animals. This means they can control their body temperature and do not have to depend on environment for their body temperature regulation. Because of this birds and mammals require optimum oxidization of glucose which would be possible with good supply of oxygen. So it is required to have separate oxygenated and de-oxygenated blood to supply the required amount of oxygen.

જવાબ :

1. Renal artery: The renal artery carries blood to the kidneys from the abdominal aorta. This blood comes directly from the heart and is sent to the-kidneys to be filtered before it passes through the rest of the body. Up to one-third of the total cardiac output per heartbeat is sent to the renal arteries to be filtered by the kidneys. Each kidney has one renal artery that supplies it with blood. The filtered blood then can exit the renal vein.
2. Kidney: The kidneys perform the essential function of removing waste products from the blood and regulating the water fluid levels. The kidneys regulate the body’s fluid volume, mineral composition and acidity by excreting and reabsorbing water and inorganic electrolytes.
3. Ureter: The ureter is a tube that carries urine from the kidney to the urinary bladder.’ There are two ureters, one attached to each kidney.

જવાબ : (a)

(b) Blood from the heart comes into the kidneys afferent and efferent arteriols from the renal arteries where it enters about 2-3 million nephrons per kidney. Then, it goes through the glomerulus a tugt or bunch of blood capillaries and get rid of some of the unwanted substances like urea, uric acid, creatinine in the blood and then continues through the renal tubules. The loop of Henley, reabsorb certain substances such as water (actually if body is dehydrated, body will send anti-diuretic hormone (ADH) to kidneys to prevent extra water from going into urine and thus saving water for body and get rid of anything else that isn’t wanted, then the urine goes through ureters to bladder and then to urethra where it is excreted out of body as urine.

જવાબ : In small intestine, complete digestion of various components of food take place. The process of digestion of food in mouth, stomach and small intestine in human
body are as follows:
Mouth: Digestion of food begins in the mouth. Saliva present in mouth contains a digestive enzyme, called salivary amylase, maltose and dextrins, which breaks down starch into sugar.
Stomach: Stomach stores and mixes the food received from the oesophagus with gastric juices. The main components of gastric juice are hydrochloric acid, mucus and pepsinogen. Hydrochloric acid dissolves bits of food and creates an acidic medium. In this medium, pepsinogen is converted to pepsin which is a protein-digesting enzyme. Mucus protects the inner lining of the stomach from the action of HC1.
Small Intestine: Small intestine is the site of complete digestion of carbohydrates, proteins and fats. Small intestine produces intestinal juice from the glands present in its wall. The intestinal juice helps in further digestion of food. Small intestine also obtains digestive juices from liver and pancreas. The liver produces bile juice that causes emulsification of fats and the pancreas produces pancreatic juice for digesting proteins and emulsified fats. This digested food is finally absorbed through the intestinal walls.

જવાબ : Amoeba is an important protozoa found in fresh water. It feeds on microscopic plants and animals present in water. The mode of nutrition in amoeba is Holozoic. And the process of obtaining food by amoeba is called phagocytosis. The different processes involved in the nutrition of amoeba are:

1. Ingestion: Ingestion is the process of taking food in the body. Amoeba is a unicellular animal, so it doesn’t have a mouth for ingestion of food. Amoeba ingests the food by encircling it by forming pseudopodia. When the food is completely encircled , the food is engulfed in the form of a bag called food vacuole.
2. Digestion: Digestion is the process of breaking the large and insoluble molecules in small and water soluble molecules. In amoeba, several digestive enzymes react on the food present in the food vacuoles and break it down into simple and soluble molecules.
3. Absorption: The food digested by digestive enzymes is then absorbed in the cytoplasm by the process of diffusion. While the undigested food remains in the food vacuole. If a large amount of food is absorbed by amoeba, the excess food is stored in the cytoplasm ih the form of glycogen and lipids.
4. Assimilation: During this step the food absorbed by the cytoplasm is used to obtain energy, growth and repair. This process of utilizing absorbed food for obtaining energy, repair and growth is called assimilation.

જવાબ : Arteries

1. Arteries carry oxygenated blood, away from the heart except pulmonary artery.
2. These are thick-walled, highly muscular except arteries of cranium and vertebral column.
3. Valves are absent.

1. Veins carry deoxygenated blood, towards the heart except pulmonary veins.
2. These are thin-walled.
3. Valves are present which provide unidirectional flow of blood.

જવાબ : (a)

(b) The functions of blood and lymph are as follows:
(i) Blood

• Oxygen is transported by the blood to the tissues of the body for the breakdown of digested food.
• Carbon dioxide is transported to the lungs by the blood plasma.
• The digested and absorbed nutrients are transported by blood to the tissues. Nitrogenous wastes are transported to the kidneys.
• It regulates the body temperature and maintains the pH of the body tissues.
• It transports various hormones from one region to another and bring about the coordination.
• It maintains water balance to constant level.
• The lymphocytes produce antibodies against the invading antigens and protect from diseases.
• It helps in rapid healing of wounds by forming a clot at the site of injury.

• It cleans the cellular environment.
• It returns proteins and tissue fluids to the blood (drainage)
• It provides a pathway for the absorption of fats and fat-soluble vitamins into the bloodstream.
• It defends the body against disease.

જવાબ : (a)

Pseudopodia serves the purpose of locomotion apart from nutrition.
(b) The salivary gland is associated with digestion of starch in human digestive tract.
It secretes saliva which contains enzyme salivary amylase. This enzyme converts starch into maltose (sugar).
(c) Gastric glands present on the walls of the stomach release HC1. HC1 creates an acidic medium, which facilitates the action of enzyme pepsin. Bile juice from liver makes the food alkaline in small intestine for the pancreatic enzymes to act.

જવાબ : (a)

(i) Gaseous exchanges between plant and the atmosphere.
(ii) Plant loses water through stomata which helps in movement of minerals from soil to leaves.
(b) Raw materials for photosynthesis: Carbon dioxide, water, chlorophyll and sunlight are the essential raw materials for photosynthesis.
(i) Carbon dioxide is a gas, which is released into the atmosphere during respiration. This gas is utilised by the autotrophic plants which enters the leaf through the stomata present on its surface during the process of photosynthesis.
(ii) Water is another requirement for photosynthesis, which is transported upward through xylem tissues to the leaves, from where it reaches the photosynthetic cells. This water then splits in the presence of sunlight and chlorophyll.
(iii) Chlorophyll is a green pigment in plants, which acts as a catalyst. It is responsible for absorption of the sun’s energy by the plant. The chlorophyll pigments are photoreceptor molecules which play a key role in the photosynthetic process. The different types of chlorophyll molecules are chlorophyll a, b, c, d, e and bacteriochlorophyll; of which chlorophyll a and b are the most common.
(iv) Light affects photosynthesis by its intensity, quality and duration. In green light, the rate of photosynthesis is minimum, while in red and blue lights the rate of photosynthesis is maximum.
Rate of photosynthesis is higher in plants getting average light of 10-12 hrs a day.
The chemical equation for photosynthesis is as follows:

જવાબ : The process of breakdown of glucose in a cell are as follows:

The first step in the breakdown of glucose both in presence of 02 and in absence of Os is same. In this step, glucose is broken down into pyruvate.
Second step which involves further breakdown of private into simple compounds can take place in two different ways:
(i) In presence of Oz: In the presence of 02, private is converted into C02 and water. Energy released during aerobic respiration is much greater than that released during an anaerobic respiration.
(ii)In absence of Oz: In the absence of 02 in yeast, pyruvate is converted into ethanol and C02 and the process is called fermentation. In absence of 02, in our muscle cells, pyruvate is converted into lactic acid. The build up of lactic acid in muscle cells causes cramps.

જવાબ : (i) Photosynthesis can be represented using a chemical equation. The overall balanced equation is

(ii) Desert plants open up their stomata during night and take in CO₂. Stomata remains close during the day time to prevent the loss of water by i transpiration. They store the CO₂ in their cells until the sun comes out and they can carry on with photosynthesis during the day time.

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