General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
461
An aquatic plant introduced from America to control pollution but turned invasive in India is:
Answer:
n aquatic plant introduced from America to control pollution but turned invasive in India is:
Eichhornia crassipes, or water hyacinth, is native to South America but spread aggressively in Indian water bodies. It clogs waterways, reduces oxygen, and harms aquatic biodiversity. Despite being introduced for ornamental and pollution-control purposes, it became one of the world’s worst invasive species.
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462
In the nitrogen cycle, soil nitrates are converted back to free nitrogen by:
Answer:
Denitrifying bacteria
Denitrifying bacteria, such as Pseudomonas, reduce nitrates to nitrogen gas, completing the nitrogen cycle. This process occurs under anaerobic conditions in soil. It helps maintain atmospheric nitrogen balance but can reduce soil fertility.
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463
Which organism is a useful biological indicator of sulfur dioxide pollution?
Answer:
Lichens
Lichens are highly sensitive to sulfur dioxide and are rarely found in polluted urban areas. Their absence indicates deteriorating air quality. This makes them reliable bioindicators for monitoring industrial pollution.
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464
The relationship between the water fern Azolla and the cyanobacterium Anabaena is:
Answer:
etween the water fern Azolla and the cyanobacterium Anabaena is:
Azolla and Anabaena share a mutualistic relationship where both partners benefit. Anabaena fixes atmospheric nitrogen for Azolla, while Azolla provides shelter and carbon sources. This relationship is widely used in rice cultivation to naturally enrich soils.
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465
The highest per capita emitter of carbon dioxide in the world is:
Answer:
Qatar
Qatar consistently ranks as the world’s highest per capita emitter of CO₂. This is due to its small population combined with intensive fossil fuel and cement production. While China and the U.S. lead in total emissions, per person, Qatar is far ahead.
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466
Identify the non–Greenhouse Gas (GHG) from the following:
Answer:
Oxygen
Greenhouse gases trap heat in the Earth’s atmosphere, contributing to global warming. Methane, nitrous oxide, and carbon dioxide are well-known GHGs. Oxygen, however, is not a greenhouse gas and plays no direct role in warming the atmosphere.
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467
Which of the following statements is NOT true?
Answer:
All of the above statements are true.
Each of the listed statements accurately reflects known scientific facts. Carbon monoxide binds to hemoglobin, impairing oxygen transport. Photochemical smog is characterized by ozone, and lead pollution historically came from fuel emissions, making option (d) correct.
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468
The word “ecology” (Ökologie) was coined in 1866 by:
Answer:
Ernst Haeckel
The German scientist Ernst Haeckel first coined the term “ecology” in 1866. He described it as the study of organisms in relation to their environment. His work laid the foundation for modern ecological science.
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469
In an ecotone, the species that become most abundant are known as:
Answer:
Edge species
Ecotones are transitional zones between two ecosystems, such as forests and grasslands. These areas experience the “edge effect,” where adaptable species thrive in abundance. Such species, called edge species, often exploit the broader range of ecological niches present.
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470
The Siberian Crane, an endangered migratory bird, regularly visits which sanctuary in India?
Answer:
rane, an endangered migratory bird, regularly visits which sanctuary in India?
Keoladeo National Park, also known as Bharatpur Bird Sanctuary in Rajasthan, is a UNESCO World Heritage Site. It is famous for hosting migratory birds, including the rare Siberian Crane, during winter. The park’s wetlands provide an ideal habitat for nesting and feeding.
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