Please do not add map data that is not requested in the instructions of a project as it can make a task more difficult to validate and requires more time to map. I believe the tree rows you added are inaccurate as nearby trees have a much greater diamiter/width.

The round building you added is not a building as it does not cast a shadow. Other nearby buildings cast a clear significant shadow in this imagery. 

Look (but do not map) beyond your task area for features you can definitely identify and use them as a reference when mapping.