hmm from what i know abstract don't have a subject...or really a man subject...then hor i think it is more on color, texture and etc...hoho...
not like landscapes where got flowers, mountains or lakes...abstract maybe a leaf against the sky, ridgeline or even just water running down....
not like portrait where got pple smiling...abstract maybe showing teeth with bracets(soori duno how to spell)
not like macro where got insect on flower...abastract maybe just the shadow against the flower to show insect is there...
hmm so my explanation abstract or not...hoho
okie u are professional...maybe u tell me loh...