group 1 food crops

1.abandon

2.adversely

3.aggregate

4.cultivation

5.fertilize

6.intensify

7.irrigation

8.obtain

9.photosynthesis

10.precipitation

group 2 disaster

1.anticipate

2.catastrophic

3.collide

4.eruption

5.famine

6.flood

7.impact

8.persevere

9.plunge

10.unleash

group 3 evolution and migration

1.adapt

2.diverse

3.evolve

4.feature

5.generation

6.inherent

7.migration

8.physical

9.process

10.survive

group 4 petroleum alternative

1.constraint

2.contamination

3.deplete

4.dispose of

5.elementally

6.emission

7.extinction

8.reservoir

9.shrink

10.stable