How did Stone Age people get to America and Australia without ships?

According to the monocentric theory, people originated in Africa and then settled in other areas of the earth. First, the development of the eastern coast of Africa went on, and about 50 thousand years ago they began to develop the Arabian Peninsula, reached the territory of China, India and Indonesia. About 40 thousand years ago, man reached the shores of Australia.

The sea level was then much lower than modern, so that the mainland of Australia extended much further. New Guinea and Australia formed one continent, Sahul. It was on this isthmus that people from Asia and Oceania came to Australia.

People got to America through the modern Bereng Strait and through Alaska. The sea froze during periods of glaciation, and the ice could easily get from Asia to North America.