Deforestation Increases Atmospheric CO2

Steps:

• Global warming stems from excess CO2 trapping heat in the atmosphere via the greenhouse effect.
• Effect 2 reduces CO2 uptake by plants, leaving more CO2 in the air.
• Effect 3 releases stored CO2 from burning forests, directly adding to emissions.
• Effects 1 and 4 involve biodiversity and soil issues, not CO2 levels.

Why B is correct:

• Deforestation boosts CO2 concentrations by limiting absorption (effect 2) and emitting gases from combustion (effect 3), per the carbon cycle where plants sequester and release CO2.

Why the others are wrong:

• A: Effect 1 causes habitat loss, not CO2 rise.
• C: Effect 4 leads to erosion, unrelated to warming.
• D: Neither 1 nor 4 directly affects CO2.

Final answer: B