Area a refers to an area just one side of a sheet or in plants and means only the orders that are still green, which represents photosynthesis capability still exists.
Leaf area means that only one side of the leaf or sheet refers only in plants and leaves are still green. It demonstrates the ability of photosynthesis is still available.
Leaf area refers to only one side of the leaf area or sheet in plants and refers only to have green leaves Which represents the photosynthetic ability still exists.