Which finding, if true, would most directly support the researchers' …

|Question 10Verbal

Source Texts

Text

Growing seasons in Alaska have been extending further into the year in response to climate warming, potentially enabling increased carbon dioxide

(C O_{2})

absorption through greater productivity of marsh cinquefoil (Comarum palustre) plants and other vegetation, but also potentially enabling increased

C O_{2}

output through greater heterotrophic respiration (

C O_{2}

generated by the activity of soil microorganisms). Hydrologist Yonghong Yi and her colleagues developed a model incorporating numerous inputs years of solar radiation and snow cover data among them to evaluate the effects of warming on the

C O_{2}

balance in Alaska, concluding that net

C O_{2}

is likely to increase if warming hastens spring snow melt.

Which finding, if true, would most directly support the researchers' conclusion?

Early snow melt extends the period in which plant species such as C. palustre can absorb

C O_{2}

but has no effect on the rate of heterotrophic respiration.

Early snow melt slows the growth of plant species such as C. palustre by reducing soil insulation, and it suppresses heterotrophic respiration.

Early snow melt reduces the amount of soil moisture available for the growth of plant species such as C. palustre, and it raises the rate of heterotrophic respiration.

Early snow melt amplifies the effect of solar radiation on the growth of plant species such as C. palustre and on the rate of heterotrophic respiration.