Concept:Global warming is the steady increase in Earth’s average temperature caused by the build-up of greenhouse gases.
Explanation:When global temperatures rise, polar ice caps and glaciers receive more heat and begin to melt.
The melted ice flows into the oceans, adding extra water and increasing the total volume of seawater.
Warmer ocean water also expands, contributing to an additional rise in sea level.
Therefore, the most direct physical result of global warming is melting ice caps and rising sea level.
Corrosion of roofing sheets is mainly linked to acid rain, not global warming.
A rise in atmospheric pressure does not follow directly from global warming.
Population explosion and rapid urbanisation are social and economic issues, not direct climatic results.
Answer:Option A — melting ice cap and rising sea level.