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
71
What is the primary driver of Earth's climate and weather patterns?
Answer:
Solar energy and the Earth's rotation
The uneven heating of the Earth's surface by the sun, combined with the Earth's rotation (Coriolis effect), creates the global wind and ocean currents that distribute heat across the planet.
72
Which of the following organisms is a 'detritivore'?
Answer:
Earthworm
Detritivores, like earthworms and woodlice, ingest and internally digest dead organic matter. Mushrooms are 'saprotrophs' because they digest organic matter externally by secreting enzymes.
73
What is 'eutrophication'?
Answer:
The enrichment of water with nutrients, leading to excessive plant growth.
Eutrophication is often caused by human activities (runoff of fertilizers/sewage). It leads to 'hypoxia' or 'dead zones' where the water no longer has enough oxygen to support fish.
74
Which biome is dominated by grasses and has very few trees due to fires and periodic droughts?
Answer:
Temperate Grassland (Prairie)
Grasslands have seasonal rainfall and rich soil. Large grazers and frequent fires prevent the establishment of woody shrubs and trees, maintaining the grass-dominated landscape.
75
What is 'biological nitrogen fixation'?
Answer:
The conversion of $N_2$ to $NH_3$ by microorganisms.
Only certain prokaryotes (like Rhizobium) have the enzyme nitrogenase required to break the strong triple bond of $N_2$ gas and convert it into ammonia.
76
Which ecological interaction is '+/-' in terms of benefits and harms?
Answer:
Predation
In predation, the predator benefits (+) by obtaining food, and the prey is harmed (-) by being killed. Parasitism and herbivory also follow this +/- pattern.
77
What is the term for a transition area between two different biomes?
Answer:
Ecotone
An ecotone (like the boundary between a forest and a grassland) often has high species diversity because it contains species from both bordering communities as well as species unique to the edge.
78
Which of the following is an 'Endemic' species?
Answer:
A species that is native to a specific, restricted geographic area.
Endemic species are found only in one place (e.g., lemurs in Madagascar). Because of their restricted range, they are often highly vulnerable to extinction from habitat loss.
79
The total dry weight of all living organisms in a particular area is:
Answer:
Biomass
Biomass represents the stored chemical energy in an ecosystem. It is usually measured as dry mass to exclude the variable weight of water in tissues.
80
What is the primary source of phosphorus for land-based ecosystems?
Answer:
The weathering of rocks
Phosphorus is a non-gaseous element. It enters the soil through the slow weathering and erosion of phosphate-containing rocks, making it one of the most slowly recycled nutrients.