the plants used to be harvested for food. the island used to be located farther south. the climate of the island used to be warmer. the fossils used to be more resistant to cold.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Finding fossils of warm-weather plants in the rock layers of a cold northern island suggests that
Possibilities:
- the plants used to be harvested for food.
- the island used to be located farther south.
- the climate of the island used to be warmer.
- the fossils used to be more resistant to cold.

the climate of the island used to be warmer.