Old World monkeys primarily inhabit Africa and Asia.

The World Health Organization is working to improve public health worldwide.

She is conducting research on the world's oldest profession.

When he had a problem due to his own actions, he remembered the phrase 'chickens come home to roost'.

The Paleolithic is the first era of human history.

The Bronze Age was an important period in human history.

The Neolithic was an important period in human history.

The Azuchi-Momoyama period was a very important time in Japanese history.

The Azuchi-Momoyama period, also known as the Oda-Nobunaga period, was a very important time in Japanese history.

The Mesolithic is the era between the Paleolithic and the Neolithic.