REMOVE

1. plants
2. rock
3. workers
4. freight cars
5. sky
6. beaches

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. buildings (structures) (1)
4. bushes (1)

More 

WHERE

1. Ensenada, Baja California … (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1949 (1)