REMOVE

1. sky
2. hats
3. men (male humans)
4. roads
5. groves (plant communities)

WHAT

1. Visual Works (hierarchy n … (1)
2. artists (visual artists) (1)
3. automobiles (1)
4. black-and-white film (1)
5. branches (plant component … (1)

More 

WHEN

1. 1960 (1)
2. 1970 (1)
3. between 1960 - 1970 (1)