Answer:
A. Organ
Explanation:
Leaf is an essential part of plant that is involved in photosynthesis and also in exchange of gases. It is made up of epidermis, which is thick one, and is present at lower and upper surface of leaf. Between upper and lower epidermis, mesophyll is present while cuticle is present outside of the epidermis. Xylem and phloem and other connective tissues are arranged in the leaf in such way that it maintains the shape as well as effective transfer of nutrients and water in the leaf. Leaf is an organ, made up of all these tissues to form a complex structure.
