UPSC NDA-1 Archives

21. Which one of the following is the correct sequence in increasing compl

Which one of the following is the correct sequence in increasing complexity ?

Join Our Telegram Channel

Protein – Organism – Tissue – Organ

Protein – Organ – Tissue – Organism

Protein – Organism – Organ – Tissue

Protein – Tissue – Organ – Organism

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

The correct sequence in increasing complexity is Protein – Tissue – Organ – Organism. This corresponds to option D.

Biological organization follows a hierarchical structure, starting from molecules and progressing to larger, more complex levels. Proteins are complex molecules. Tissues are groups of similar cells. Organs are composed of different tissues working together. An organism is a complete living being made up of organ systems (which are made of organs).

The general hierarchy of biological organization is: atoms < molecules < organelles < cells < tissues < organs < organ systems < organism < population < community < ecosystem < biosphere. Proteins are a type of molecule.

22. Which of the following is not a part of compound microscope ?

Which of the following is not a part of compound microscope ?

Join Our Telegram Channel

Mirror

Stage

Clip

Retina

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

The correct option is D. The retina is a part of the eye, the organ that perceives the light and forms the image, and is not a component of a compound microscope itself.

A compound microscope is an optical instrument with several components, including the mirror (or light source), stage (for holding the specimen), clips (to hold the slide on the stage), objective lenses, eyepiece, body tube, focus knobs, etc., all working together to magnify an object.

The image formed by the microscope is viewed by the observer through the eyepiece, and this image is ultimately focused onto the retina of the observer’s eye. While the retina is crucial for seeing the magnified image, it is functionally distinct from the microscope’s structure.

23. Which of the following statements regarding animal cell membrane is co

Which of the following statements regarding animal cell membrane is correct ?

Join Our Telegram Channel

They are composed of phospholipids only.

They are composed of proteins only.

They are composed of phospholipids and proteins only.

They are composed of phospholipids, proteins and cholesterol (lipid).

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

The animal cell membrane is a complex structure composed of a phospholipid bilayer, various proteins embedded within or associated with the bilayer, and cholesterol. Phospholipids form the basic structural framework. Proteins perform diverse functions like transport, signaling, and recognition. Cholesterol, a type of lipid, is present in animal cell membranes and plays a crucial role in regulating membrane fluidity and stability. Therefore, the animal cell membrane is composed of phospholipids, proteins, and cholesterol.

The fluid mosaic model is the widely accepted model describing the structure of the cell membrane, depicting it as a fluid bilayer of lipids with proteins embedded or associated with it.

Plant cell membranes also have phospholipid bilayers and proteins, but they typically lack cholesterol. Instead, they contain other sterols. Cell membranes also contain carbohydrates, usually attached to proteins (glycoproteins) or lipids (glycolipids), which are involved in cell recognition and adhesion, although the options only list phospholipids, proteins, and cholesterol as primary constituents.

24. Consider the following characteristics of a grassland: 1. An extensi

Consider the following characteristics of a grassland:

1. An extensive area of mid latitude grasslands are devoid of trees and shrubs.
2. The climate is characterised by hot summers, cold winters and relatively low rainfall occurring mainly in spring and summer.
3. In humid parts, grasses grow to a meter or more in height.

On the basis of the above characteristics, select the correct grassland from the options given below :

Steppes

Prairies

Savanna

Pampas

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

The characteristics described – extensive mid-latitude grassland devoid of trees/shrubs, a climate with hot summers, cold winters, relatively low rainfall mainly in spring/summer, and tall grasses in humid areas – are most typical of the Steppes grassland biome. This description aligns well with the continental climate (Dfa/Dfb or BSk in Köppen classification) found across the Eurasian Steppe, which experiences significant seasonal temperature variations and distinct dry periods. While Prairies share some characteristics, the climate description, particularly “relatively low rainfall mainly in spring and summer” and pronounced hot/cold extremes, is highly representative of the Steppe climate.

Mid-latitude grasslands exist on multiple continents but have regional names (Steppes in Eurasia, Prairies in North America, Pampas in South America, Veld in Africa). Their existence is primarily determined by a climate that is too dry for forests but wet enough for grasses to thrive.

Savanna is a tropical grassland with scattered trees, not a mid-latitude grassland, and its climate is characterized by a hot wet season and a hot dry season. Pampas has a more temperate climate than the extreme continental conditions described. While Prairies fit many of the criteria, the description strongly leans towards the classic Steppe climate profile.

Join Our Telegram Channel

25. Consider the following statements regarding soils: 1. Soils having a

Consider the following statements regarding soils:

1. Soils having a very high content of sodium and calcium and pH of more than 7.0 are alkaline soils.
2. Black cotton soil had developed on the Deccan basaltic lava under hot and humid conditions.
3. Laterite soils are characterised by a deep weathered layer from which silica has been leached.

Which of the statements given above is/are correct ?

Join Our Telegram Channel

1 only

1 and 2 only

2 and 3 only

1, 2 and 3

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Statement 1 is correct. Alkaline soils are defined as soils having a pH greater than 7. High content of base cations like sodium and calcium contribute to a higher pH, leading to alkaline conditions. Sodic soils (high sodium) and calcareous soils (high calcium carbonate) are common types of alkaline soils. Statement 2 is correct. Black cotton soil (Regur soil) is characteristic of the Deccan Trap region in India and is formed from the weathering of basaltic lava rocks under conditions including high temperatures and distinct wet and dry seasons, which facilitates the formation of expansive clays and cracking. Statement 3 is correct. Laterite soils are formed through intense weathering and leaching in hot, humid climates with distinct wet and dry seasons. This process, called laterization or desilication, involves the removal of silica and bases, leaving behind a concentration of iron and aluminum oxides in a deep weathered layer.

Soil classification and properties are influenced by parent material, climate, topography, organisms, and time. Different soil types exhibit distinct physical, chemical, and biological characteristics.

Alkaline soils can pose challenges for agriculture due to potential nutrient deficiencies or toxicities at high pH levels. Black soils are known for their high clay content and moisture retention but can be difficult to cultivate when wet or dry. Laterite soils are often poor in nutrients due to intense leaching but can be used for crops like cashew, tapioca, and groundnut after appropriate management.

26. Consider the following statements regarding ‘fronts’ : 1. The moveme

Consider the following statements regarding ‘fronts’ :

1. The movement of a front causes a slow change in weather in the area over which it moves.
2. Cold fronts are associated with thunderstorms.
3. Warm front is the boundary between an advancing mass of warm air where it is overriding and rising above a mass of colder air.

Which of the statements given above is/are correct ?

1 only

1 and 2 only

2 and 3 only

1, 2 and 3

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Statement 2 is correct. Cold fronts involve the rapid lifting of warm air by an advancing cold air mass, leading to steep pressure gradients and instability, which frequently results in the formation of cumulonimbus clouds and thunderstorms, heavy rain, and gusty winds. Statement 3 is correct. A warm front is defined as the boundary where an advancing mass of warm air overrides and rises above a colder air mass. The warm air, being less dense, slides up over the wedge of colder air. Statement 1 is incorrect. While warm fronts typically cause gradual and prolonged weather changes (like steady rain), cold fronts often bring about rapid and significant weather changes (sudden temperature drop, intense precipitation, thunderstorms). Thus, saying “slow change” for *all* fronts is incorrect.

Atmospheric fronts are the boundaries between air masses with different temperature, humidity, and density characteristics. Their passage is associated with significant weather changes. Cold fronts are generally steeper and move faster than warm fronts.

Other types of fronts include stationary fronts (where air masses meet but neither is strong enough to replace the other) and occluded fronts (formed when a cold front overtakes a warm front). Each type of front is associated with characteristic cloud formations, precipitation patterns, and temperature/pressure changes.

Join Our Telegram Channel

27. Which of the following statements regarding clouds is/are correct ?

Which of the following statements regarding clouds is/are correct ?

Join Our Telegram Channel

1. Clouds are classified on the basis of altitude and their form.
2. According to altitude they are classified as High, Middle and Low clouds.
3. Stratus, Nimbostratus and Stratocumulus are high clouds.

Select the answer using the code given below :

1 only

1 and 2 only

2 and 3 only

1, 2 and 3

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Statement 1 is correct. Clouds are indeed classified based on their altitude (High, Middle, Low, and vertical development) and their form or appearance (e.g., cirrus, cumulus, stratus). Statement 2 is correct. The classification based on altitude includes High clouds (above 6 km), Middle clouds (between 2 and 6 km), and Low clouds (below 2 km). Statement 3 is incorrect. Stratus, Nimbostratus, and Stratocumulus are classified as low clouds (with bases typically below 2 km). High clouds include Cirrus, Cirrostratus, and Cirrocumulus.

The main cloud types based on form are Cirrus (fibrous), Cumulus (heaped/lumpy), and Stratus (layered). Combinations and variations of these forms, along with their altitude, lead to the more specific cloud classifications. ‘Nimbus’ or ‘nimbostratus’ indicates precipitation.

Clouds of vertical development, such as Cumulus and Cumulonimbus, span multiple altitude layers. Cumulonimbus clouds, for instance, can have their base in the low layer but extend up to the high layer, producing thunderstorms. Middle clouds often have the prefix ‘Alto-‘, e.g., Altocumulus and Altostratus.

28. Which of the following statements regarding Regur soil is/are correct

Which of the following statements regarding Regur soil is/are correct ?

1. It is a light coloured, clayey and fertile soil.
2. It is developed on Deccan basaltic lava under hot and humid conditions.
3. Cotton is extensively cultivated in this soil.

Select the answer using the code given below :

Join Our Telegram Channel

1 and 2

2 and 3

2 only

3 only

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Statement 3 is correct. Regur soil, also known as Black Cotton soil, is famous for its suitability for cotton cultivation due to its high clay content which allows it to retain moisture effectively. Statement 2 is also correct. Black soils are predominantly found in the Deccan Trap region and are formed by the weathering of basaltic lava rocks. While not exclusively under consistently humid conditions (alternating wet and dry periods are key for their cracking property), they develop under hot temperatures and seasonal rainfall characteristic of the region. Statement 1 is incorrect; Regur soils are dark grey to black in colour, not light-coloured.

Regur soils are characterized by their dark color, clayey texture, high moisture retention capacity, and tendency to develop deep cracks during dry periods. They are rich in minerals but can be deficient in nitrogen, phosphorus, and organic matter.

The parent material for Regur soils in the Deccan region is primarily basalt. The black color is attributed to compounds like titaniferous magnetite and often associated with humus accumulation in the presence of clays. While cotton is the most famous crop grown in these soils, they are also used for cultivating crops like jowar, wheat, sugarcane, and groundnuts.

29. Which of the following statements regarding Barchan is/are correct ?

Which of the following statements regarding Barchan is/are correct ?

1. It is a crescent shaped mound of sand, which is deposited by the wind blowing constantly from one direction in a desert.
2. The windward side has a convex steep slope with maximum height at the centre.
3. Two ends of Barchan are called horns and point opposite to the direction the wind blows.

Select the answer using the code given below :

Join Our Telegram Channel

1 only

1 and 2 only

2 and 3 only

1, 2 and 3

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Statement 1 is correct. A Barchan is indeed a crescent-shaped sand dune formed by wind blowing predominantly from one direction in a desert environment.

Barchans are one of the most common types of sand dunes. Their shape is a direct result of unidirectional wind flow and limited sand supply.

Statement 2 is incorrect. The windward side of a barchan dune has a gentle, convex slope where sand is pushed up by the wind. The leeward side, also known as the slip face, has a much steeper, concave slope (close to the angle of repose for sand, around 30-34 degrees) where sand avalanches down. The maximum height is at the crest, just before the slip face.
Statement 3 is incorrect. The two ends of the crescent shape are called horns. These horns point downwind, in the direction that the wind is blowing, because the sand moves faster around the edges of the dune than at the center. They point *in* the direction of the wind flow, not opposite to it.

30. Which among the following are essential constituents of Portland cemen

Which among the following are essential constituents of Portland cement ?

Join Our Telegram Channel

Sand, lime, clay

Silica, alumina, lime

Silica, lime, graphite powder

Sand, graphene, clay

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Portland cement is primarily made from materials containing calcium oxide (lime), silicon dioxide (silica), aluminum oxide (alumina), and iron oxide. The main raw materials are typically limestone (for lime) and clay or shale (for silica, alumina, and iron). These materials are heated in a kiln to produce clinker, which is then ground into fine powder with a small amount of gypsum added. Option B lists Silica, Alumina, and Lime, which are the essential oxide components derived from these raw materials, forming the bulk of the cement clinker.

The major chemical components of Portland cement clinker are tricalcium silicate (alite), dicalcium silicate (belite), tricalcium aluminate (celite), and tetracalcium aluminoferrite (ferrite). These are formed from the reaction of lime (CaO), silica (SiO2), alumina (Al2O3), and iron oxide (Fe2O3) during calcination.

Sand is commonly used as an aggregate in concrete (a mixture of cement, aggregates, and water), but it is not a constituent of cement itself. Graphite powder and graphene are forms of carbon and are not standard components of Portland cement. Clay is a raw material containing silica and alumina, used in cement production, but the essential *constituents* within the clinker are the oxides (silica, alumina, lime, etc.) derived from the raw materials.