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Multiple Choice
What is the primary source of the carbon dioxide used in photosynthesis by plants?
A
Glucose stored in leaves
B
The atmosphere
C
Soil minerals
D
Water absorbed by roots
Verified step by step guidance
1
Understand the process of photosynthesis: Photosynthesis is the process by which plants convert light energy into chemical energy, using carbon dioxide (CO₂) and water (H₂O) to produce glucose (C₆H₁₂O₆) and oxygen (O₂).
Identify the role of carbon dioxide in photosynthesis: Carbon dioxide is one of the key reactants in the photosynthesis equation. It is combined with water in the presence of sunlight and chlorophyll to form glucose and oxygen.
Determine the source of carbon dioxide: Plants obtain carbon dioxide from the atmosphere through small openings in their leaves called stomata. The carbon dioxide diffuses into the leaf cells where photosynthesis occurs.
Eliminate incorrect options: Glucose stored in leaves is a product of photosynthesis, not a source of carbon dioxide. Soil minerals and water absorbed by roots do not provide carbon dioxide; they contribute other essential nutrients and water for the process.
Conclude that the atmosphere is the primary source of carbon dioxide used in photosynthesis, as plants absorb it directly from the air.