السؤال 6

What happens to most of the oxygen a leaf makes while it is photosynthesising?

It is taken back in as one of the raw materials
It passes out of the leaf into the air as a waste productالإجابة الصحيحة
It is stored in the leaf until the plant needs it at night
It is carried down to the roots and used there

الشرح

Photosynthesis produces far more oxygen than the plant has any use for, so nearly all of it diffuses out of the leaf into the surrounding air as waste. The gas the reaction takes in as a raw material is a different one; a leaf has no store in which it could hold this gas back until dark; and the roots receive no delivery of it either, because the oxygen around their cells comes from the air trapped between the soil particles.

الشرح

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