Question

The bulk fixation of carbon through photosynthesis takes place in:

• A. Crop plant and tropical rain forest
• B. Tropical rain forest
• C. Crop plants
• D. Oceans

Hint:

While oceans contribute most globally, crop plants are vital for carbon fixation on land, especially in agriculture.

Answer 1

The Correct Option is C

Crop plants contribute significantly to carbon fixation, especially in managed agricultural ecosystems.
Tropical rain forests are important but contribute less compared to oceanic phytoplankton globally.
Oceans (especially phytoplankton) contribute about 50% of global carbon fixation.
The options mix terrestrial and aquatic sources; crop plants have major localized carbon fixation roles.

Answer 2

Alternate approach - separate "largest global contributor" from "bulk, concentrated fixation":
Oceanic phytoplankton are often quoted for a large share of global photosynthesis, but that fixation is spread thinly across enormous, dispersed water volumes rather than being concentrated as harvestable biomass.
Tropical rainforests fix substantial carbon per unit area but occupy a comparatively limited and shrinking total land area worldwide.
Crop plants, being intensively cultivated across vast, concentrated agricultural land with high planting density and managed inputs, together account for the greatest bulk of measurable, concentrated carbon fixation among the options given, distinguishing them from the more diffuse contributions of forests or oceans.