One half-life of a radioactive isotope has passed when: A. all the parent nuclei have become daughter nuclei.
B. the number of daughter nuclei is twice the number of parent
nuclei.
C. the number of daughter nuclei is half the number of parent nuclei.
D. the numbers of parent and daughter nuclei are equal.

What is your question then

It has been around since 1858 so b. false

Many archeologists and anthropologists disagree with dr. thorne's view.  thorne strongly believes that what many calls "homo erectus"  was in fact  homo sapiens,  and that they migrated out of africa almost 2 million years ago and dispersed throughout europe and asia. that's way different  from what scientists have always believed about the evolution of the species.

Ibelieve it would be a