Model 1 - Comparison of Photosynthesis and Respiration, highlighting the interdependence of these processes in plant cells.

Let’s go step by step to answer the questions based on Model 1.

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Question 1a: What two substances are needed for photosynthesis?

Look at the top part of the diagram — it shows “Photosynthesis” happening in the chloroplast. The arrow pointing INTO the chloroplast says:

> CO₂ + H₂O → (with light energy) → C₆H₁₂O₆ + O₂

So, the things going IN (needed) are:
- Carbon dioxide (CO₂)
- Water (H₂O)

✔ Answer: Carbon dioxide and water

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Question 1b: What two products of photosynthesis?

Products are what come OUT of the process. From the same equation above:

> ...→ C₆H₁₂O₆ + O₂

That means:
- Glucose (C₆H₁₂O₆) — a sugar that stores energy
- Oxygen (O₂) — released into the air

✔ Answer: Glucose and oxygen

*(Note: In your image, you wrote “GLUCOSE and OXYGEN (C6H12O6 + O2)” — that’s correct!)*

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Now let’s double-check using the diagram:

- Arrows going INTO chloroplast: CO₂ and H₂O → those are reactants (needed).
- Arrows coming OUT of chloroplast: glucose (goes to mitochondria or stored) and O₂ (released) → those are products.

Everything matches.

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Final Answer:
1a. Carbon dioxide and water
1b. Glucose and oxygen