Biogeochemical Cycles — Homi Bhabha Exam Biology MCQs with Solutions
Free Homi Bhabha Exam Biology Biogeochemical Cycles MCQs with step-by-step solutions (6 questions). Part of Ecosystem & Environmental Management. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Biogeochemical Cycles · medium · theory
The continuous circulation of water between the Earth and the atmosphere is called the:
A. nitrogen cycle
B. water cycle ✓ Correct
C. carbon cycle
D. rock cycle
Solution: The water cycle involves evaporation, condensation and precipitation.
Q2 — Biogeochemical Cycles · hard · theory
The conversion of atmospheric nitrogen into compounds usable by plants is called:
A. nitrogen fixation ✓ Correct
B. denitrification
C. respiration
D. nitrification only
Solution: Nitrogen fixation converts inert N₂ into usable nitrogen compounds, often by bacteria.
Q3 — Biogeochemical Cycles · medium · theory
The process that adds oxygen to the atmosphere in the oxygen cycle is:
A. decomposition
B. combustion
C. photosynthesis ✓ Correct
D. respiration
Solution: Photosynthesis by green plants releases oxygen into the air.
Q4 — Biogeochemical Cycles · hard · theory
Bacteria that live in the root nodules of leguminous plants and fix nitrogen are:
A. Plasmodium
B. yeast
C. Lactobacillus
D. Rhizobium ✓ Correct
Solution: Rhizobium bacteria in legume root nodules fix atmospheric nitrogen.
Q5 — Biogeochemical Cycles · medium · theory
In the carbon cycle, carbon dioxide is removed from the air mainly by:
A. photosynthesis ✓ Correct
B. burning of fuels
C. respiration
D. volcanic eruption
Solution: Plants remove CO₂ from the atmosphere during photosynthesis.
Q6 — Biogeochemical Cycles · hard · theory
Biogeochemical cycles are important because they:
A. recycle essential nutrients so that life can continue ✓ Correct
B. only occur in oceans
C. destroy nutrients permanently
D. stop energy flow
Solution: These cycles continuously recycle nutrients (carbon, nitrogen, water) between living things and the environment.