According to paragraph 2, what is the primary effect of carb…

Accоrding tо pаrаgrаph 2, what is the primary effect оf carbon dioxide? 2. According to the Union of Concerned Scientists, carbon dioxide (one of the greenhouse gases human activity emits that traps heat on the planet) increases plant growth rate. That, in turn, increases the quantity and ​potency​ of pollen. Additionally, rising temperatures — caused by increasing carbon dioxide levels — make pollen-producing plants' growing seasons longer. That, of course, extends allergy season, too. Higher temperatures can also lead individual plants to produce more pollen and can expand the geographic ranges of those plants.