As a result of depletion of the ozone layer, more ultraviolet (UV) radiation reaches the Earth, and this lowers the production of phytoplankton. What follows from the lower production of phytoplankton?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → It affects other aquatic organisms
Phytoplankton are tiny plants in water that many other water animals depend on. When UV radiation lowers their production, it affects other aquatic organisms too.
Option (1) It causes a rise in the sea level — Incorrect. A rise in sea level is a result of global warming, through melting polar ice.
Option (2) It causes skin cancer in humans — Incorrect. UV radiation itself seems responsible for skin cancer; this does not follow from less phytoplankton.
Option (3) It influences the growth of terrestrial plants — Incorrect. This is a separate effect of UV radiation, on land plants.
Option (4) It affects other aquatic organisms — Correct. This follows from the fall in phytoplankton.
NCERT (2026-27): “Box 7.2: Ozone Depletion … As a result of depletion of the ozone layer, more ultraviolet (UV) radiation comes to Earth and causes damage to living organisms. UV radiation seems responsible for skin cancer in humans; it also lowers production of phytoplankton and thus affects other aquatic organisms. It can also influence the growth of terrestrial plants. …” |