General Science - MCQ Practice Questions
General Science in SSC, railway and state exams stays at school level, which makes it one of the few sections where full marks are realistic. Practice covers physics fundamentals such as motion, light and electricity, chemistry basics including elements and compounds, and biology topics like the human body, nutrition and diseases. Answers stay at the depth the paper actually uses instead of drifting into degree level theory.
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Which of the following diseases is NOT caused by a virus?
Understanding:
We need to identify the disease among the given options that is not caused by a virus.
Step 1: Classifying the diseases by causative agents
Step 2: Identifying the non-viral disease
Cholera is a bacterial infection caused by Vibrio cholerae. It spreads through contaminated water and food, causing severe watery diarrhoea and dehydration. The other three diseases in the list are all caused by viruses.
Answer:
Cholera is the disease that is NOT caused by a virus — it is caused by the bacterium Vibrio cholerae.
Quick Tip:
Cholera is a water-borne disease — the key prevention strategy is access to clean drinking water and proper sanitation, not vaccination (unlike the other viral diseases listed).
Which of the following hormones is directly responsible for regulating blood sugar levels in the human body?
Understanding:
We need to identify the hormone primarily responsible for regulating blood glucose (sugar) levels.
Step 1: Role of each hormone
Step 2: Why Insulin is correct
Insulin is the primary hormone that regulates blood glucose. When blood sugar rises after a meal, the pancreas secretes insulin, which facilitates the uptake of glucose by body cells and its storage as glycogen in the liver. Deficiency or resistance to insulin leads to Diabetes Mellitus.
Answer:
Insulin is the hormone directly responsible for regulating blood sugar levels.
Quick Tip:
Insulin lowers blood sugar (anabolic), while Glucagon (also from the pancreas) raises blood sugar — they act as antagonists to maintain glucose homeostasis.
BCG vaccine, used to provide protection against Tuberculosis, stands for which of the following?
Understanding:
We need to identify the full form of the BCG vaccine used against Tuberculosis.
Step 1: Historical background of BCG
The BCG vaccine was developed by French bacteriologists Albert Calmette and Camille Guérin at the Pasteur Institute. They created a weakened (attenuated) strain of Mycobacterium bovis to develop immunity against Tuberculosis.
Step 2: Full form
BCG stands for Bacillus Calmette-Guérin, named after its two developers. It is one of the oldest and most widely used vaccines in the world and is part of India's Universal Immunisation Programme (UIP), given to newborns.
Answer:
BCG stands for Bacillus Calmette-Guérin.
Quick Tip:
The BCG vaccine was first used in humans in 1921. In India, it is administered at birth as part of the national immunisation schedule to protect against severe forms of TB in children.
Which of the following diseases is caused by the protozoan Plasmodium vivax?
Understanding:
We need to identify the disease caused by the protozoan Plasmodium vivax.
Step 1: Mapping protozoans to diseases
Step 2: About Plasmodium vivax and Malaria
Plasmodium vivax is one of four species of Plasmodium that causes malaria in humans (others: P. falciparum, P. malariae, P. ovale). It causes Benign Tertian Malaria, where fever recurs every 48 hours. Malaria is transmitted by the bite of the female Anopheles mosquito.
Answer:
Malaria is the disease caused by the protozoan Plasmodium vivax.
Quick Tip:
Among the Plasmodium species, P. falciparum causes the most severe and potentially fatal form of malaria — Malignant Tertian Malaria — and is responsible for the majority of malaria deaths globally.
Haemophilia is a disease related to which of the following conditions?
Understanding:
We need to identify what Haemophilia is and how it affects the body.
Step 1: Understanding Haemophilia
Haemophilia is a hereditary (genetic) bleeding disorder in which the blood does not clot properly. It occurs due to the deficiency or dysfunction of specific clotting factors — Factor VIII in Haemophilia A (most common) and Factor IX in Haemophilia B. As a result, even minor injuries can lead to prolonged bleeding.
Step 2: Ruling out other options
Step 3: Genetic nature
Haemophilia is an X-linked recessive disorder. It predominantly affects males, while females are usually carriers. The gene responsible for the clotting factors is located on the X chromosome.
Answer:
Haemophilia is characterised by the inability of blood to clot normally due to deficiency of clotting factors.
Quick Tip:
Haemophilia is often called the 'Royal Disease' because it spread through the royal families of Europe, descended from Queen Victoria, who was a carrier.
Which of the following vitamins is synthesised in the human skin upon exposure to sunlight?
Understanding:
We need to identify which vitamin is produced in the human skin when it is exposed to sunlight.
Step 1: The process of Vitamin D synthesis
When ultraviolet B (UVB) radiation from sunlight falls on the skin, it converts a cholesterol derivative (7-dehydrocholesterol) present in the skin into Vitamin D3 (cholecalciferol). This is then processed by the liver and kidneys into its active hormonal form, calcitriol.
Step 2: Role of Vitamin D
Vitamin D is essential for the absorption of calcium and phosphorus in the intestine, which is critical for bone mineralisation and strength. Deficiency of Vitamin D leads to Rickets in children and Osteomalacia in adults.
Step 3: Why other vitamins are incorrect
Answer:
Vitamin D is the vitamin synthesised in the human skin upon exposure to sunlight.
Quick Tip:
Vitamin D is unique in that it functions both as a vitamin (obtained from diet) and as a hormone (synthesised by the body). It is the only vitamin the body can produce on its own from non-food sources.
Which of the following greenhouse gases has the highest Global Warming Potential (GWP) over a 100-year period?
Understanding:
We need to identify which greenhouse gas has the highest Global Warming Potential (GWP) over a 100-year time horizon among the given options.
Step 1: Define GWP
Global Warming Potential is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific period, relative to carbon dioxide (GWP = 1).
Step 2: Compare GWP values of listed gases
Step 3: Identify the correct answer
Sulphur hexafluoride has by far the highest GWP among the options listed, making it the most potent greenhouse gas per unit mass.
Answer:
Sulphur hexafluoride (SF₆) has the highest Global Warming Potential over a 100-year period among the given options.
Quick Tip:
SF₆ is widely used in electrical switchgear and transformers. Despite being released in small quantities, its extremely high GWP and long atmospheric lifetime make it a significant concern for climate change.
The 'Chipko Movement', which aimed at protecting forests, originated in which Indian state?
Understanding:
We need to identify the Indian state where the Chipko Movement originated.
Step 1: Historical context of the Chipko Movement
The Chipko Movement (meaning 'to hug' or 'to cling') was a non-violent environmental movement in which villagers, especially women, hugged trees to prevent them from being felled by logging contractors.
Step 2: Location of origin
The movement began in 1973 in the Chamoli district of what was then Uttar Pradesh — the region is now part of the state of Uttarakhand (formed in 2000). The key figures associated with the movement include Sundarlal Bahuguna, Gaura Devi, and Chandi Prasad Bhatt.
Step 3: Eliminate other options
Answer:
The Chipko Movement originated in Uttarakhand (formerly part of Uttar Pradesh).
Quick Tip:
The Chipko Movement is considered one of the earliest and most successful grassroots environmental movements in India and inspired similar forest conservation efforts worldwide.
Which layer of the Earth's atmosphere contains the ozone layer that shields the Earth from harmful ultraviolet radiation?
Understanding:
We need to identify the atmospheric layer that contains the ozone layer.
Step 1: Structure of Earth's atmosphere
The atmosphere is divided into layers based on temperature gradients:
Step 2: Location of the ozone layer
The ozone layer is concentrated in the stratosphere, approximately between 15 and 35 km above Earth's surface. Ozone (O₃) in this layer absorbs most of the Sun's harmful ultraviolet (UV-B and UV-C) radiation, preventing it from reaching Earth's surface.
Step 3: Significance
Depletion of the stratospheric ozone layer — caused primarily by chlorofluorocarbons (CFCs) — leads to increased UV radiation reaching Earth, which can cause skin cancer, cataracts, and damage to ecosystems.
Answer:
The ozone layer is found in the stratosphere.
Quick Tip:
Do not confuse stratospheric ozone (beneficial — shields UV) with tropospheric ozone (harmful — a pollutant and component of smog at ground level).
The concept of 'Ecological Footprint' measures which of the following?
Understanding:
We need to identify what the term 'Ecological Footprint' specifically measures.
Step 1: Definition of Ecological Footprint
The Ecological Footprint is a metric developed by Mathis Wackernagel and William Rees in the early 1990s. It quantifies the amount of biologically productive land and water area that a human population requires to produce the resources it consumes and to absorb the waste it generates, using prevailing technology.
Step 2: Eliminate incorrect options
Step 3: Confirm correct answer
The ecological footprint is a comprehensive sustainability indicator encompassing food, water, energy, land for waste absorption, and built-up land — expressed in global hectares (gha).
Answer:
Ecological Footprint measures the biologically productive land and water needed to sustain resource use and absorb waste for a given population.
Which of the following is classified as a 'Hotspot of Biodiversity' in India?
Understanding:
We need to identify which region in India is officially recognised as a Biodiversity Hotspot.
Step 1: What is a Biodiversity Hotspot?
A biodiversity hotspot is a biogeographic region that is both a significant reservoir of biodiversity and is threatened by human habitation. To qualify, a region must have at least 1,500 endemic vascular plant species and have lost at least 70% of its original habitat.
Step 2: India's Biodiversity Hotspots
India has four recognised biodiversity hotspots:
1. Western Ghats
2. Eastern Himalayas (Indo-Burma region)
3. Sundaland (includes Nicobar Islands)
4. Indo-Burma region
Step 3: Evaluate the options
Answer:
The Western Ghats is a recognised Biodiversity Hotspot in India.
Quick Tip:
India hosts 4 of the world's 36 biodiversity hotspots. The Western Ghats alone is home to over 5,000 species of flowering plants, 139 mammal species, 508 bird species, and 179 amphibian species.
Which of the following international agreements specifically deals with the control of trade in endangered species of wild fauna and flora?
Understanding:
We need to match the international agreement that specifically regulates trade in endangered species.
Step 1: Review each agreement
Step 2: Identify the correct agreement
CITES directly addresses the issue of trade in endangered species by listing species in three appendices based on their level of protection needed and controlling or banning their international trade accordingly.
Answer:
CITES is the international agreement that controls trade in endangered species of wild fauna and flora.
Quick Tip:
CITES currently protects over 38,000 species of animals and plants. India is a signatory and has listed species such as tigers, elephants, and rhinos under its provisions.
Eutrophication of water bodies is primarily caused by an excess of which of the following nutrients?
Understanding:
We need to identify the nutrients primarily responsible for eutrophication of water bodies.
Step 1: What is Eutrophication?
Eutrophication is the process by which a water body becomes overly enriched with nutrients, leading to excessive growth of algae and aquatic plants (algal blooms). This reduces dissolved oxygen in the water, creating dead zones and harming aquatic life.
Step 2: Primary nutrients responsible
Nitrogen (N) and Phosphorus (P) are the two key limiting nutrients that trigger eutrophication. They enter water bodies mainly through:
Step 3: Eliminate other options
Answer:
Eutrophication is primarily caused by excess nitrogen and phosphorus in water bodies.
Quick Tip:
The process of oxygen depletion following an algal bloom is called hypoxia. The dead zones formed in water bodies due to eutrophication are well documented in lakes such as Dal Lake (Kashmir) and parts of the Baltic Sea.
Which of the following correctly defines 'Biomagnification'?
Understanding:
We need to identify the correct definition of 'Biomagnification' from the given options.
Step 1: Define Biomagnification
Biomagnification (also called biological magnification or bioamplification) refers to the progressive increase in the concentration of a toxic substance — such as DDT, mercury, or PCBs — in organisms at each successive trophic level of a food chain. The substance is not metabolised or excreted efficiently, so it accumulates in body fat or tissues.
Step 2: Typical example
In the DDT example:
This caused thinning of eggshells in raptors, leading to population declines.
Step 3: Eliminate incorrect options
Answer:
Biomagnification is the increase in concentration of toxic substances at successively higher trophic levels in a food chain.
Quick Tip:
Biomagnification is different from bioaccumulation. Bioaccumulation refers to the build-up of a substance within a single organism, while biomagnification refers to the increase in concentration across trophic levels.
The 'Red Data Book' maintained by the International Union for Conservation of Nature (IUCN) is used for which of the following purposes?
Understanding:
We need to identify the purpose of the IUCN Red Data Book (Red List).
Step 1: What is the IUCN Red List?
The IUCN Red List of Threatened Species (commonly called the Red Data Book) is the world's most comprehensive inventory of the conservation status of biological species. It was established in 1964 and classifies species into categories such as:
Step 2: Purpose
The primary purpose is to document the conservation status of threatened species of plants, animals, fungi, and other organisms to guide conservation efforts and policy decisions globally.
Step 3: Eliminate other options
Answer:
The IUCN Red Data Book documents the conservation status of threatened species of plants, animals, and fungi.
Quick Tip:
As of recent assessments, over 42,000 species are listed as threatened with extinction on the IUCN Red List. India's Great Indian Bustard is listed as Critically Endangered.
Which of the following correctly describes the primary cause of 'Acid Rain'?
Understanding:
We need to identify the primary cause of acid rain from the given options.
Step 1: Chemistry of Acid Rain
Acid rain forms when sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) are released into the atmosphere — mainly from burning fossil fuels, vehicle emissions, and industrial processes. These gases react with water vapour, oxygen, and other chemicals in the atmosphere to form sulphuric acid and nitric acid, which fall as acid rain.
Step 2: Key reactions
The main reactions are:
Step 3: pH of acid rain
Normal rain has a pH of about 5.6 (slightly acidic due to dissolved CO₂ forming carbonic acid). Acid rain has a pH below 5.6, sometimes as low as 4 or less.
Step 4: Eliminate incorrect options
Answer:
Acid rain is primarily caused by emissions of sulphur dioxide and nitrogen oxides that react with atmospheric moisture to form sulphuric and nitric acids.
Quick Tip:
Acid rain causes damage to forests, aquatic ecosystems, soil, and heritage structures (such as the Taj Mahal, which has been affected by acid rain from nearby industries).
Which of the following technologies is used in 'Li-Fi' communication systems?
Understanding:
This question asks about the underlying technology used in Li-Fi (Light Fidelity) wireless communication systems.
Step 1: What is Li-Fi?
Li-Fi is a wireless communication technology proposed by Professor Harald Haas in 2011. Unlike Wi-Fi, which uses radio waves, Li-Fi transmits data using visible light emitted by LED bulbs. The light is modulated at very high speeds, imperceptible to the human eye, to encode and transmit data.
Step 2: Why visible light?
LED lights can be switched on and off millions of times per second. This rapid switching forms the basis of data transmission in Li-Fi, enabling speeds potentially far exceeding conventional Wi-Fi.
Step 3: Eliminating other options.
Radio waves are used in Wi-Fi and mobile networks. Infrared is used in TV remotes and some short-range communication, not Li-Fi. Microwave signals are used in radar, satellite, and some broadband communication technologies.
Answer:
Li-Fi uses visible light (from LED sources) to transmit data wirelessly.
Quick Tip:
Li-Fi stands for Light Fidelity — the word 'light' itself is a strong hint that visible light is the medium of communication.
Which of the following is the correct full form of 'GPS' as used in navigation technology?
Understanding:
This question asks for the correct expansion of the abbreviation GPS used in navigation and location-tracking technology.
Step 1: Origin of GPS.
GPS was developed by the United States Department of Defense. It is a satellite-based radio navigation system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth.
Step 2: What each letter stands for.
G — Global, P — Positioning, S — System. The full form is Global Positioning System.
Step 3: Eliminating other options.
None of the other expansions — General Prediction Satellite, Geo-Positional Signal, or Global Precision Sensor — correspond to any recognized technology or standard.
Answer:
The correct full form of GPS is Global Positioning System.
Quick Tip:
India's own regional navigation satellite system is called NavIC (Navigation with Indian Constellation), developed by ISRO as a counterpart to GPS.
Which of the following best describes the function of a 'firewall' in computer networks?
Understanding:
This question asks about the primary function of a firewall in the context of computer network security.
Step 1: Definition of a Firewall.
A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic. It establishes a barrier between a trusted internal network and untrusted external networks such as the Internet, based on a defined set of security rules.
Step 2: What a firewall does NOT do.
A firewall does not speed up connections — that is the role of caching or compression tools. It does not convert digital to analog signals — that is the function of a modem. It does not store backup copies of files — that is the role of backup software or cloud storage.
Step 3: Conclusion.
The core function of a firewall is packet filtering and traffic monitoring based on security policies, making option B the only correct description.
Answer:
A firewall monitors and controls network traffic based on predetermined security rules.
Quick Tip:
Firewalls can be hardware-based, software-based, or both. Most operating systems like Windows come with a built-in software firewall.
Which generation of mobile network technology introduced the concept of 'packet switching' and enabled mobile internet access for the first time?
Understanding:
This question asks which generation of mobile technology first introduced packet switching and mobile internet capability.
Step 1: Understanding 1G.
1G (First Generation) networks, introduced in the 1980s, were analog systems used only for voice calls. They had no data services.
Step 2: Understanding 2G.
2G networks, introduced in the early 1990s (GSM standard), were the first digital mobile networks. They introduced packet switching through GPRS (General Packet Radio Service) and EDGE technologies, enabling limited mobile internet access such as WAP browsing and MMS.
Step 3: Understanding 3G and 4G.
3G provided significantly faster internet speeds and multimedia support, while 4G (LTE) brought broadband-level mobile internet. However, the first introduction of packet switching and mobile internet was with 2G technology.
Step 4: Conclusion.
2G was the first generation to move from circuit switching (used in voice calls) to packet switching for data, enabling mobile internet access.
Answer:
2G was the first mobile network generation to introduce packet switching and mobile internet access.
Quick Tip:
Remember the progression: 1G = Analog voice; 2G = Digital voice + basic internet; 3G = Multimedia internet; 4G = High-speed broadband; 5G = Ultra-low latency + massive connectivity.