Question

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1. in this performance task, you will learn about research related to photosynthesis. irina set up an experiment to study photosynthesis in spinach. she wanted to find how light intensity affects photosynthesis. she prepared a solution of water and baking soda. when dissolved in water, baking soda breaks down to produce small amounts of carbon dioxide. irina used a straw to cut small disks from spinach leaves. she placed the disks into a cup filled with the baking soda solution. irina then placed some of this solution, with leaf disks, in a syringe. she pulled back on the syringe to remove gases inside the leaf disks. next, she poured the solution back into the cup. the leaf disks sank to the bottom of the cup. finally, irina set a lamp above the cup. figure 1 shows the tools irina used in setting up her experiment.

as the leaf disks photosynthesized, tiny bubbles formed around their edges. the disks began to float. irina calculated the percentage of leaf disks that were floating after 10 minutes. then she repeated the experiment, using light bulbs of different brightness. irinas results are shown in figure 2.
what evidence from irinas experiment can be used to show the relationship among light, oxygen, and sugar in photosynthesis?
a. the amount of oxygen in the water affects the amount of light absorbed by the leaves and the amount of sugar that can be released into the water.
b. the amount of sugar in the leaves limits the amount of light that can be absorbed during photosynthesis and the amount of oxygen that can be produced.
c. light intensity affect the amount of oxygen that can be released into the water and the amount of sugar that can be produced.
d. light intensity limits the amount of sugar that can be absorbed during photosynthesis and the amount of oxygen that can be released into water.

Explanation:

• In photosynthesis, light is used to convert carbon dioxide and water into sugar and oxygen.
• The experiment uses leaf disks floating (due to oxygen bubbles) as an indicator of photosynthesis.
• As light intensity (independent variable) increases, the percentage of floating disks (dependent variable, related to oxygen production) increases. This shows a relationship between light (input) and oxygen (output of photosynthesis). Sugar is also produced in photosynthesis, and the oxygen production (as shown by floating disks) is related to the light - driven process that also produces sugar.

Answer:

C. Light intensity affect the amount of oxygen that can be released into the water and the amount of sugar that can be produced.