MCQ practice · SSC Biology Board questions · Chapter 4: Bioenergetics
Which is an external factor of the photosynthesis process?
Think it through first, then pick an option.
- a Oxygen
- b Carbohydrate
- c Potassium
- d Enzyme
Answer and explanation
Correct answer: a Oxygen
Oxygen is an external factor; a higher concentration lowers the rate and a lower one raises it.
Why the other options are wrong
- b Carbohydrate: The amount of carbohydrate is an internal factor; piling up in the leaf slows the rate.
- c Potassium: Potassium is an internal factor; its shortage lowers the rate.
- d Enzyme: Enzyme is an internal factor, since it belongs inside the cell; the question asks for an external one.
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