UPSC CDS-1

41. Match List I with List II and select the correct answer using the code

Match List I with List II and select the correct answer using the code given below the lists :

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List I
(Blood Vessel)		 List II
(Function)
A. Pulmonary artery 1. Carries blood from lungs to heart
B. Capillaries 2. Carries blood to heart muscle
C. Coronary artery 3. Connection between arteries and veins
D. Pulmonary vein 4. Carries blood from heart to lungs

Code :

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A B C D
(a) 4 3 2 1
(b) 4 2 3 1
(c) 1 2 3 4
(d) 1 3 2 4
4 3 2 1
4 2 3 1
1 2 3 4
1 3 2 4
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The correct matching is A-4, B-3, C-2, D-1.
A. Pulmonary artery: This is the only artery in the body that carries deoxygenated blood. It carries blood from the right ventricle of the heart to the lungs for oxygenation (Function 4).
B. Capillaries: These are the smallest blood vessels, forming a network that connects arterioles (small arteries) and venules (small veins). They are the site of exchange of substances between blood and tissues (Function 3 represents this connection).
C. Coronary artery: These arteries branch from the aorta and supply oxygenated blood to the heart muscle itself (Function 2).
D. Pulmonary vein: These are the only veins in the body that carry oxygenated blood. They carry blood from the lungs back to the left atrium of the heart (Function 1).
Understanding the circulatory system, particularly the unique roles of pulmonary vessels and coronary arteries, is key to answering this question.

42. The disease rickets develops in children due to the deficiency of :

The disease rickets develops in children due to the deficiency of :

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Vitamin C
Vitamin D
Vitamin A
Vitamin B
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The disease rickets develops in children due to the deficiency of Vitamin D.
Vitamin D is crucial for the absorption of calcium and phosphorus, which are essential for the proper development and maintenance of bones. Deficiency of Vitamin D leads to impaired mineralization of bones, causing them to become soft and weak. In children, this condition is known as rickets, characterized by bone deformities.
Deficiency of Vitamin C causes scurvy. Deficiency of Vitamin A can cause night blindness and other vision problems. Deficiency of various Vitamin B complex vitamins can cause different diseases, such as Beriberi (B1), Pellagra (B3), etc.

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43. Plants prepare glucose in the process of :

Plants prepare glucose in the process of :

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respiration
photosynthesis
degradation
mineral absorption
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Plants prepare glucose in the process of photosynthesis.
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigment. During photosynthesis, plants convert light energy into chemical energy in the form of glucose (a sugar). This process uses carbon dioxide and water as raw materials and releases oxygen as a byproduct.
Respiration is the process where organisms break down glucose to release energy. Degradation refers to the breaking down of complex substances. Mineral absorption is the uptake of mineral nutrients from the soil.

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44. Which one of the following statements is correct about the cell membra

Which one of the following statements is correct about the cell membrane ?

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It is made up of cellulose.
It is a permeable structure for all substances.
It is flexible and enables the cell to engulf many materials.
It does not allow diffusion of gases like oxygen and carbon dioxide.
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Statement C is correct about the cell membrane.
The cell membrane is primarily composed of a lipid bilayer with embedded proteins (fluid mosaic model). This structure is flexible and allows the cell to change shape and engulf substances from the external environment through processes like endocytosis (e.g., phagocytosis and pinocytosis), which is essential for functions like nutrition or defence.
Statement A is incorrect; cellulose is the main component of the plant cell wall, not the cell membrane. Statement B is incorrect; the cell membrane is selectively permeable, meaning it controls which substances can pass through it. Statement D is incorrect; small nonpolar molecules like oxygen and carbon dioxide can readily diffuse across the lipid bilayer of the cell membrane.

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45. Suppose, due to an accident, the delicate lining of the mouth and the

Suppose, due to an accident, the delicate lining of the mouth and the oesophagus of a person is injured. In this case, which one of the following tissues will be affected ?

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Smooth muscle
Cuboidal epithelium
Squamous epithelium
Striated muscle
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The delicate lining of the mouth and the oesophagus is primarily composed of squamous epithelium.
Epithelial tissue forms the lining of body cavities, surfaces, and organs. The inner lining (mucosa) of the mouth and oesophagus, which is subject to abrasion from food passage, is lined with stratified squamous epithelium. This type of epithelium is composed of multiple layers of flattened cells, providing a protective barrier. Injury to this lining directly affects this epithelial tissue.
Smooth muscle is found in the muscular layers of the oesophagus wall, responsible for peristalsis (moving food down), but not the lining itself. Cuboidal epithelium is typically found in glands and kidney tubules. Striated muscle (skeletal muscle) is involved in voluntary movements, such as swallowing initiation, but does not form the lining.

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46. Which one of the following statements is not correct with regard to

Which one of the following statements is not correct with regard to genetically modified organisms ?

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In this technique a gene from one organism is isolated and transferred to the cell of another organism.
This technique has applications only in plants.
Genes for insect resistance may spread from crop plants to wild plants.
To produce a transgenic animal the novel genes are inserted at a very early stage of development.
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Statement B is not correct.
Genetically modified organism (GMO) technology involves transferring genes between organisms. While widely applied in plants (e.g., Bt cotton, herbicide-resistant crops), it also has significant applications in animals (e.g., transgenic animals for research, disease models, or production of specific proteins) and microorganisms (e.g., bacteria engineered to produce insulin or enzymes). Therefore, the application is not limited only to plants.
Option A correctly describes a fundamental step in genetic modification. Option C highlights a valid environmental concern regarding potential gene flow from GM crops to wild relatives. Option D accurately describes the method for creating transgenic animals by introducing the desired gene into a fertilized egg or early embryo to ensure it is present in all cells.

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47. Which one of the following statements is true when non-metals are diss

Which one of the following statements is true when non-metals are dissolved in water ?

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They produce basic oxides.
They produce acidic oxides.
They produce neutral oxides.
They provide hydroxides.
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While non-metals themselves generally do not react with water to produce oxides, their oxides (non-metal oxides) are typically acidic oxides. When these acidic oxides dissolve in water, they react to form acidic solutions. For example, CO2 dissolves in water to form carbonic acid, SO2 forms sulfurous acid, and SO3 forms sulfuric acid. Thus, non-metal oxides are characterized as producing acidic solutions when dissolved in water.
Oxides are classified as acidic, basic, amphoteric, or neutral. Non-metal oxides generally react with water to form acids, classifying them as acidic oxides. Metal oxides, in contrast, generally react with water to form bases, classifying them as basic oxides.
Some non-metals like chlorine react with water in a redox process (disproportionation) to form acidic solutions (HCl and HOCl). However, the options provided relate to oxides and hydroxides. The most common and general property associated with non-metals in this context (especially when contrasted with metals forming basic oxides/hydroxides) is the acidic nature of their oxides and the resulting solutions when these oxides dissolve in water.

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48. The number of saturated and unsaturated bonds in cyclohexane are :

The number of saturated and unsaturated bonds in cyclohexane are :

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9 and 0 respectively.
18 and 3 respectively.
18 and 0 respectively.
9 and 3 respectively.
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Cyclohexane (C6H12) is a cyclic alkane. Its structure consists of a six-membered ring of carbon atoms, with each carbon atom bonded to two other carbon atoms and two hydrogen atoms. All bonds in cyclohexane are single bonds. A single bond is considered a saturated bond in contrast to double or triple bonds which are unsaturated bonds. There are 6 carbon-carbon single bonds forming the ring and 12 carbon-hydrogen single bonds. Thus, there are a total of 6 + 12 = 18 saturated bonds (single bonds) and 0 unsaturated bonds (double or triple bonds).
In organic chemistry, molecules containing only single bonds between carbon atoms and single bonds to hydrogen atoms are considered saturated. The term “saturated bond” commonly refers to a single bond, while “unsaturated bond” refers to double or triple bonds.
The formula C6H12 matches the general formula for cycloalkanes (CnH2n) or alkenes. Cyclohexane is a cycloalkane. A six-carbon chain alkane (hexane) has the formula C6H14. The formation of a ring involves the loss of two hydrogen atoms and results in 6 C-C single bonds and 12 C-H single bonds.

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49. While burning hydrocarbon fuels, if we see a yellow flame with lots of

While burning hydrocarbon fuels, if we see a yellow flame with lots of black smoke, it means that the fuel is :

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made of saturated hydrocarbons.
made of unsaturated hydrocarbons.
burning completely.
wet.
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A yellow flame with lots of black smoke indicates incomplete combustion. This occurs when there is insufficient oxygen for the fuel to burn completely. Unsaturated hydrocarbons, which have a higher carbon-to-hydrogen ratio than saturated hydrocarbons, tend to undergo incomplete combustion more readily and produce sooty flames (yellow flame and black smoke) when the oxygen supply is limited.
Complete combustion produces a clean, often blue, flame and primarily carbon dioxide and water. Incomplete combustion produces a yellow, luminous, and sooty flame, along with carbon monoxide and unburnt carbon particles (soot), which appear as black smoke. The likelihood of incomplete combustion depends on the fuel type and the oxygen supply.
Saturated hydrocarbons (like alkanes) typically burn with cleaner, often blue, flames compared to unsaturated hydrocarbons (like alkenes, alkynes, and aromatic hydrocarbons) which have higher carbon content and are more prone to incomplete combustion leading to sooty, yellow flames.

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50. What is the number of moles of ‘He’ in 104 g of helium gas ?

What is the number of moles of ‘He’ in 104 g of helium gas ?

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52
26
13
6.5
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The number of moles of a substance is calculated by dividing the given mass by its molar mass. The atomic mass of Helium (He) is approximately 4 g/mol. Therefore, 104 g of helium gas contains 104 g / 4 g/mol = 26 moles.
The mole is the SI unit for the amount of substance, defined as containing as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. For elements, the molar mass in grams per mole is numerically equal to the atomic mass in atomic mass units (amu).
Helium is a noble gas and exists as single atoms (monatomic gas), so ‘He’ represents a helium atom, and its molar mass is its atomic mass. If it were a diatomic gas like oxygen (O2), the molar mass would be twice the atomic mass of O.

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