Describe at least one evidence for evolution that scientists use to show common ancestry among organisms

Which taxon group is more specific, in regards to organisms that are in that group? mammalia animalia

The body is protected against harmful flu viruses by

Consider the last statement in the prompt: "people take such environmental factors into account in their choices when deciding where to live." do all people have a choice as to where they live? what factor plays a key role in this decision and may therefore play a large role in determining quality of life?