Answer: Increased skin cancer (melanoma), cataracts, immune suppression, and damage to marine ecosystems (phytoplankton).
- A Increased plant growth resulting from a noticeably higher rate of photosynthetic activity overall under most conditions encountered
- B Increased skin cancer (melanoma), cataracts, immune suppression, and damage to marine ecosystems (phytoplankton)
- C Cooler surface temperatures caused by greater UV reflection off high-altitude cloud cover as frequently observed in practice
- D Increased global rainfall caused by enhanced ionization occurring within the upper atmosphere in many documented cases
Correct answer: B. Increased skin cancer (melanoma), cataracts, immune suppression, and damage to marine ecosystems (phytoplankton)
Explanation: UV-B causes DNA damage (thymine dimers), which the ozone layer normally prevents. Increased UV-B exposure leads to: (1) Skin cancer (melanoma, BCC, SCC); (2) Cataracts; (3) Immune suppression; (4) Damage to phytoplankton (base of marine food chain); (5) Reduced agricultural yields.
Sunlight passes through the atmosphere and warms the surface; the surface re-radiates this energy as infrared heat, which greenhouse gases (CO₂, CH₄, water vapour) absorb and trap - a naturally beneficial process that intensifies into global warming as gas concentrations rise from human activity.
Concept context
Pollution, global warming, ozone depletion, deforestation, and sustainability. Important for NEET and general awareness.