One day, Peter put a leaf in hot water. After a while, he noted that a lot of air bubbles appeared on the lower surface of the leaf, but only a few air bubbles were found on the upper surface. Where did the air bubbles come from (name the part)?

The air bubbles are oxygen coming out of the leaf

Explanation:

Though the leaf is in hot water, it is still using light to continue on the path of photosynthesis. Now, this path of photosynthesis involves letting oxygen out of the leaf. Thus, this oxygen is the one that we see as bubbles coming out of the water.

The reason for having more air bubbles at the lower surface than at the upper surface is because the leaf cells at the lower surface of the leaf possess faster photosynthetic rate in releasing

oxygen.

continuous conducting path for current, power supply