Upper epidermis, lower epidermis, cuticle, chloroplasts, xylem, phloem, guard cell, stomata, palisade layer, spongy layer, mesophyll, vascular bundle
Mesophyll as well
Palisade layer spongy layer upper epidermis lower epidermis stoma
The internal parts of a leaf is upper epidermis,lower epidermis,spongy layer and many more
There are many parts of its .. You don't know just re search you can research it on google.com .. Or in yahoo.com
The photosynthesis of course, how dumb
Pigmentation and rest two ones I don't know...
Ewan