A plant with variegated (two-coloured) leaves was left in the sun for several hours. A piece of one of its leaves were then detached (removed) and tested for sugar.

Explain, as fully as you can, why the yellow region of the leaf had not produced sugar. (5 marks)

The yellow leaf was not exposed to the sun so it can't produce sugar.

Explanation:

The yellow region of the leaf didn't produce sugar because it wasn't exposed to sunlight. Part of the leaf was exposed to the sun, thus this leaf produced sugar, while the yellow part of the leaf did not because it was not exposed to the sunlight.