Is it wise to sleep under a tree during (a.) the day (b.) at night? Give reasons.

It is not wise to sleep under the tree at night. Because at night, the plants and trees perform the process of respiration where they absorb oxygen and releases carbon dioxide.

While, it is wise to sleep under the tree in the day time, as during the day time the plants perform photosynthesis where trees absorb carbon dioxide and release oxygen gas.