Final answer:
Lower sea levels during the last ice age made human migration to Australia and North America possible.
Step-by-step explanation:
During the last Ice Age, lower sea levels made it possible for human migration to various areas. One of these areas was Australia. The land bridge between Papua New Guinea and Australia allowed early humans to walk to Australia. This is supported by evidence of settlements in Australia that are at least 45,000 years old. Additionally, humans were able to migrate to North America from Asia by crossing the Bering Strait, which was exposed due to lower sea levels.