Long answer IV — task. Science CBSE, Class 7.

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A food stall owner was preparing dough for making bhaturas. He added a pinch of yeast and sugar to the dough and left it in a warm place. After few hours, the dough had risen. There was a sour smell too.

1. Why did the dough rise?

The yeast's respiration releases oxygen, raising dough.
The yeast's transpiration releases carbon dioxide, raising dough.
The yeast's respiration releases carbon dioxide, raising dough.
The yeast's transpiration releases oxygen, raising dough.

2. Why did the dough smell sour?

Yeast aerobic respiration produces foul-smelling alcohol.
Yeast anaerobic respiration produces foul-smelling lactic acid.
Yeast aerobic respiration produces pleasant -smelling alcohol.
Yeast anaerobic respiration produces foul-smelling alcohol.

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27. Long answer IV

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