1.   Imagine the response of early humans to fire caused by volcanoes or spontaneous combustion.

2.   By measuring how closely current populations are related, the authors trace the routes by which early humans migrated around the earth.

3.   And early humans were an active bunch, working hard physically every day to obtain food and shelter.

4.   As part of the research, Hammer examined the Y chromosomes of chimpanzees, whose lineage diverged from that of early humans about six million years ago.

5.   Because mammoths mostly stayed in one place, so did the early humans who thrived on them.

6.   A pillar of anthropology has been that early humans could not have embarked on an intercontinental trek without advanced implements.

7.   Also, early humans might have discovered fire when they first noticed a blaze in a lightning-ignited forest.

8.   China is a treasure trove of archaeological wonders, some of which can provide valuable information on early humans.

9.   Early humans probably had few sweat glands, like chimpanzees, and those were mainly located on the palms of their hands and the bottoms of their feet.

10.   Fukui believes that when early humans formed communities, they had to develop ways to alleviate sexual tensions.