22. Due to the decline in fertility that tends to accompany wealth, human population is expected to stabilize at near 9 billion by 2050.
23. A mere 12,000 years ago, a species closely related to the modern humans had been living on an Indonesian island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
24. Despite Charles Darwin’s theories were abused for racism, Darwin himself always considered all modern humans to belong to one species.