Final answer:
The theory that states humans originated through Africa, Asia, and Europe at the same time is called the "out of Africa" theory, which suggests that modern humans emerged in Africa and then spread out to populate different parts of the world, replacing other human species.
Step-by-step explanation:
The theory that states that humans originated through Africa, Asia, and Europe at the same time is known as the "out of Africa" theory or the replacement model of human evolution.
According to this theory, modern humans first emerged in Africa approximately 200,000 years ago and then spread out to populate different parts of the world, including Asia and Europe, replacing other human species. This theory is supported by genetic evidence that shows close ties between the genomes of people in Africa and those tested outside of Africa, indicating a common ancestry.