Assertion : Deforestation increases carbon dioxide concentration in the atmosphere.
Reason : Deforestation may lead to desertification.

Answer

B

Explanation

Deforestation is the conversion of forested areas to non-forested ones. One of the major effects of deforestation is enhanced carbon dioxide concentration in the atmosphere because trees that could hold a lot of carbon in their biomass are lost with deforestion. Deforestation also causes loss of biodiversity due to habitat destruction, disturbs hydrological cycle, causes soil erosion and may lead to desertification.