Question

Stomata are pores on the surfaces of the leaves and stems of plants that regulate gas exchange between the plants and the atmosphere.

Researchers found that the stomata density on the leaves of a species of plant change as the concentration of CO2CO2 in the atmosphere changes. When grown at 350 ppmppm CO2CO2 the plant has an average density of 300 stomata per mm2mm2, but when grown at 400 ppmppm CO2CO2 the plant has an average density of 250 stomata per mm2mm2.

Which of the following best describes how the ratio of the density of stomata (stomata per mm2mm2) per CO2CO2 concentration (ppmppm CO2CO2) changes as the CO2CO2 concentration increases?

• The ratio decreases from 0.860.86 to 0.630.63, because fewer stomata are needed at higher CO2CO2 concentrations.

  A

• The ratio decreases from 1.61.6 to 1.21.2, because fewer stomata are needed at higher CO2CO2 concentrations.

  B

• The ratio increases from 0.630.63 to 0.860.86, because more stomata are needed at higher CO2CO2 concentrations.

  C

• The ratio increases from 1.21.2 to 1.61.6, because more stomata are needed at higher CO2CO2 concentrations.

Answer 1

The correct answer is-

A- The ratio decreases from 0.860.86 to 0.630.63, because fewer stomata are needed at higher CO2CO2 concentrations.

Lower the Co2 concentration, higher is the stomata density.