Photosynthesis

Question 1

Read the passage below. "Plants use photosynthesis to convert carbon dioxide and water into glucose and oxygen using sunlight. The glucose provides chemical energy for the plant and can be transferred to herbivores when they eat the plant. When organisms respire, they break down glucose, releasing carbon dioxide and water back into the environment." Which statement best explains how photosynthesis contributes to the cycling of matter and the flow of energy in an ecosystem?

Accepted Answer

Photosynthesis captures solar energy and stores it in glucose, which later releases energy when organisms consume the plant, while the carbon atoms in glucose become part of the food chain and are returned to the atmosphere as CO₂ during respiration.

Answer

Photosynthesis converts water into oxygen and carbon dioxide into glucose, which eliminates the need for organisms to respire.

Answer

Photosynthesis directly provides oxygen for animals to breathe, but it does not affect the movement of carbon or the storage of energy in ecosystems.

Answer

Photosynthesis creates glucose that remains permanently stored in plant tissues, preventing carbon from re‑entering the atmosphere.

Question 2

A sealed terrarium contains a flowering plant, a rabbit that eats the plant’s leaves, and a hawk that eats the rabbit. Over time, the terrarium’s atmosphere remains stable, and the organisms continue to grow. Which explanation best describes how photosynthesis contributes to both the cycling of matter and the flow of energy in this closed system?

Accepted Answer

Photosynthesis uses sunlight to turn carbon dioxide and water into glucose, storing solar energy in chemical bonds; the glucose provides the organic matter that moves through the rabbit and hawk, and when they respire, the stored energy is released and carbon dioxide is returned to the plant, completing the cycle.

Answer

Photosynthesis removes carbon from the terrarium by turning carbon dioxide into solid carbon in the plant’s leaves, so the carbon is stored permanently and does not cycle back to the atmosphere.

Answer

Photosynthesis converts sunlight directly into heat, which the rabbit and hawk use for energy; the carbon dioxide produced by the animals is a waste product that does not re-enter the plant.

Answer

Photosynthesis produces oxygen for the rabbit and hawk to breathe, and the oxygen is the only substance that cycles back to the plant, while the plant’s glucose is not used by the animals.

Question 3

Liam is studying how his sunflower seedlings grow. He learns that the green pigment in the leaves, chlorophyll, helps the plant use sunlight. Which sentence best explains the role of chlorophyll in this process?

Accepted Answer

Chlorophyll absorbs light energy and changes it into chemical energy that the plant stores as glucose.

Answer

Chlorophyll stores the glucose that the plant makes during photosynthesis.

Answer

Chlorophyll releases oxygen directly from the air into the leaf cells.

Answer

Chlorophyll moves water from the roots up through the stem to the leaves.

Try three questions

Liam is studying how his sunflower seedlings grow. He learns that the green pigment in the leaves, chlorophyll, helps the plant use sunlight. Which sentence best explains the role of chlorophyll in this process?

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