Question

rising levels of carbon dioxide most likely
○ have a greater detrimental effect on the land than the sea.
○ have a greater detrimental effect on the sea than the land.
○ can increase productivity on the land and the sea.
○ can decrease productivity on the land and the sea.

Explanation:

Rising CO₂ levels cause ocean acidification (harmful to marine life, coral reefs, etc.) and climate change impacts on land (but ocean impacts like acidification are more direct and severe in many aspects for marine ecosystems). Also, while CO₂ can initially boost plant growth on land (fertilization effect), long - term climate change (heatwaves, droughts) and ocean acidification (harming primary producers like phytoplankton) lead to overall decreased productivity. But the key here is the comparative harm to sea vs land. Ocean acidification and warming have profound negative impacts on marine ecosystems (coral bleaching, species loss), and while land has issues, the sea is more detrimentally affected in terms of the unique impacts of CO₂ on ocean chemistry. Also, the option about increasing productivity is short - term or limited (land plants might have short - term growth, but marine productivity drops due to acidification). The option about greater harm to sea is more accurate as ocean acidification is a major consequence.

Answer:

B. have a greater detrimental effect on the sea than the land.