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
401
The upper zone of aquatic ecosystems is dominated by:
Answer:
Plankton
Phytoplankton and zooplankton dominate the sunlit (euphotic) zone. Benthos live on or in the bottom sediments. Plankton form the base of aquatic food webs.
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402
In ecosystems, which of the following shows a one-way flow?
Answer:
one-way flow?
Energy enters as sunlight, flows through trophic levels, and dissipates as heat—unidirectionally. Matter (C, N, K) cycles. Hence energy flow is one-way, while nutrients recycle.
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403
Predator–prey dynamics: which statement is INCORRECT?
Answer:
Predator populations most often eliminate prey populations.
In stable systems, predators rarely exterminate prey; oscillations tend toward dynamic balance. Functional and numerical responses track prey abundance. Adaptations like camouflage and fecundity aid prey persistence.
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404
Approximate percentage of Earth’s water that is freshwater:
Answer:
pproximate percentage of Earth’s water that is freshwater:
Only ~2.5% is freshwater, and most is locked in ice or groundwater. Accessible surface freshwater is a tiny fraction. This scarcity underlines the need for careful management.
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405
“Development that meets present needs without compromising future generations” defines:
Answer:
Sustainable development
The Brundtland Report (1987) popularized this definition. It integrates environmental stewardship, social equity, and economic viability. Policy frameworks worldwide draw on this concept.
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406
Oxygen is returned to the atmosphere mainly by:
Answer:
Photosynthesis
Plants, algae, and cyanobacteria split water and release O₂ during photosynthesis. Respiration consumes oxygen. At planetary scale, photosynthesis is the net source maintaining atmospheric oxygen.
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407
Which of the following is a renewable resource?
Answer:
renewable resource?
Living populations can be renewable if harvest ≤ regeneration. Minerals and fossil fuels are non-renewable on human timescales. Sustainable aquaculture keeps stocks replenished.
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408
Demand for a resource does not typically change with changes in:
Answer:
Technology
Technology most directly shifts supply (cost and methods), not consumer demand. Demand varies with income, tastes, and macroeconomic conditions. Some tech can indirectly influence demand, but the textbook effect is on supply.
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409
Which statement is NOT correct about heavy use of fertilizers and pesticides?
Answer:
They are eco-friendly
Excess agrochemicals degrade soils, contaminate water, and harm beneficial organisms. Over time, productivity can fall due to salinization and biota loss. Hence, heavy use is not eco-friendly.
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410
The death of the last individual of a species is called:
Answer:
Extinction
Extinction is the irreversible loss of a species when the final individual dies. “Endangered” denotes risk status, not the outcome. Preventing extinction hinges on habitat protection and threat mitigation.
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