The scientific evidence is mixed as to whether companionship of a dog can enhance human physical health and psychological wellbeing. Studies suggesting that there are benefits to physical health and psychological wellbeing have been criticised for being poorly controlled, and finding that "[t]he health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies have shown that people who keep pet dogs or cats exhibit better mental and physical health than those who do not, making fewer visits to the doctor and being less likely to be on medication than non-guardians.
Studies that people are better off with dogs have been criticized for being what?
poorly controlled

It is speculated by some archaeologists that Sumerian speakers were farmers who moved down from the north, after perfecting irrigation agriculture there. The Ubaid pottery of southern Mesopotamia has been connected via Choga Mami transitional ware to the pottery of the Samarra period culture (c. 5700 – 4900 BC C-14) in the north, who were the first to practice a primitive form of irrigation agriculture along the middle Tigris River and its tributaries. The connection is most clearly seen at Tell Awayli (Oueilli, Oueili) near Larsa, excavated by the French in the 1980s, where eight levels yielded pre-Ubaid pottery resembling Samarran ware. According to this theory, farming peoples spread down into southern Mesopotamia because they had developed a temple-centered social organization for mobilizing labor and technology for water control, enabling them to survive and prosper in a difficult environment.[citation needed]
How many levels of pre-Ubaid pottery were excavated by the French in the 1980s?
eight

Four separate and distinct state universities are located in Houston. The University of Houston is a nationally recognized Tier One research university, and is the flagship institution of the University of Houston System. The third-largest university in Texas, the University of Houston has nearly 40,000 students on its 667-acre campus in southeast Houston. The University of Houston–Clear Lake and the University of Houston–Downtown are stand-alone universities; they are not branch campuses of the University of Houston. Located in the historic community of Third Ward is Texas Southern University, one of the largest historically black colleges and universities in the United States.
What kind of college is Texas Southern University?
largest historically black