Which one aid in gaseous exchange in leaves and young stems?

Stomata are small pores found primarily on the surface of leaves and young stems in plants. As part of the photosynthesis process, they play an important role in gaseous exchange by allowing carbon dioxide to diffuse into the leaf and oxygen to diffuse out of the leaf.

Lenticels are small pores found on the surface of older, corky stems that are used for gas exchange between the stem's internal tissues and the air.

The cuticle is a waxy layer that covers the surface of leaves and stems, protecting them from water loss and environmental damage, but it does not aid in gaseous exchange.

Pinocytes are cells found in the spongy mesophyll of the leaf, where photosynthesis takes place, but they do not participate in gaseous exchange.