The main reason for the difference in the mass extinction occurring today and previously is the pace of the current extinction. The extinction is taking place globally and involves hundreds of species at the same time. In less than 50 years, we have lost numerous species. In contrast to this, previously during the mass extinction, only a few species were lost, and other managed to survive. But, not the status is opposite due to the magnitude of the extinction.
Prokaryotes- lack a cell nucleus, unicellular, in the bacteria and archaea domain, lack mitochondria and chloroplast, microscopic
eukaryotes- contains a cell nucleus, multicellular, only in the eukarya domain, contains mitochondria and chloroplast, not microscopic
The similarities between bones of humans and other animals shows that every living creature on earth has a common ancestor, even if that common ancestor is as simple as a sing-celled organism.
