Leaf anatomy. did i label this diagram correctly?

Yes, you've labelled them correctly. For your reference, here are a few details for each leaf structure in the labels.

Cuticle: Also can be called as waxy cuticle, it can help reduce water loss from the leaf, since it is impermeable to water. It is usually thicker in the top of the leaf comparing to the bottom side of the leaf, as the sunlight shining on the top of the leaf can increase the chance of water evaporation.

Upper epidermis: They're cells which act as barriers. They can prevent the entry of diseases. They're also so thin and transparent that sunlight can be passed through.

Palisade mesophyll cells: They're the main location for photosynthesis, where the plant make energy by using sunlight. Chloroplasts, which absorbs sunlight, are mostly in these cells, (although they also exist in other leaf parts, but not as many).

Xylem and Phloem: They're collectively called the vascular bundle, or vein. Xylem transports water and mineral ions from soil to leaf, and phloem transports sugar and amino acids from places of production (leaf) to places for usage or storage.  

Spongy mesophyll cells: They also have a few chloroplasts, but not as many as palisade mesophyll cells. They're loosely packed to allow gas to pass through and exchange.

Lower epidermis: similar function to upper epidermis.

For further notice, note that the missing structures from the diagram are guard cells and stomata, usually lies in the lower epidermis. Stomata are pores which allows waste products from photosynthesis (oxygen) to evaporate away and carbon dioxide from the air outside to enter the leaf. Guard cells are just the cells around the stomata, controlling the size of the stomata to increase or reduce water loss/carbon dioxide intake.

c

explanation:

b. the carbon cycle ensures living things have a source of hydrogen