How many people have lived on the earth? (approx 50,000BC-2011)   Answer here

How long do experts think humans have lived in England?   Answer here

On 31.10.2011 a monumental event happened to the human population. Can you guess?   Answer here

How long is a human tapeworm?   Answer here

How long does a human red blood cell last?   Answer here

What is the average length of a human tapeworm?   Answer here