Input: Read this: The Sumerian city-states rose to power during the prehistoric Ubaid and Uruk periods. Sumerian written history reaches back to the 27th century BC and before, but the historical record remains obscure until the Early Dynastic III period, c. the 23rd century BC, when a now deciphered syllabary writing system was developed, which has allowed archaeologists to read contemporary records and inscriptions. Classical Sumer ends with the rise of the Akkadian Empire in the 23rd century BC. Following the Gutian period, there is a brief Sumerian Renaissance in the 21st century BC, cut short in the 20th century BC by Semitic Amorite invasions. The Amorite "dynasty of Isin" persisted until c. 1700 BC, when Mesopotamia was united under Babylonian rule. The Sumerians were eventually absorbed into the Akkadian (Assyro-Babylonian) population.
Question: What history goes back to 2700's BC?

Output: unanswerable

Input: Read this: Each of these four dialects was associated with an independent kingdom on the island. Of these, Northumbria south of the Tyne, and most of Mercia, were overrun by the Vikings during the 9th century. The portion of Mercia that was successfully defended, and all of Kent, were then integrated into Wessex under Alfred the Great. From that time on, the West Saxon dialect (then in the form now known as Early West Saxon) became standardised as the language of government, and as the basis for the many works of literature and religious materials produced or translated from Latin in that period.
Question: What became the standard language in the 900's?

Output: unanswerable

Input: Read this: The study of the molecular and cellular components that comprise the immune system, including their function and interaction, is the central science of immunology. The immune system has been divided into a more primitive innate immune system and, in vertebrates, an acquired or adaptive immune system. The latter is further divided into humoral (or antibody) and cell-mediated components.
Question: Vertebrates also have what type of immune system component?

Output: acquired or adaptive immune system

Input: Read this: The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina.
Question: Are all species of algae similar?

Output:
many differences