Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Context: FreeBSD is a free Unix-like operating system descended from Research Unix via the Berkeley Software Distribution (BSD).
Question: The FreeBSD is based upon what?
berkeley software distribution

Context: Chronic myeloid leukemia (CML) is characterized by the presence of the Philadelphia chromosome, which is associated with a balanced translocation involving chromosomes 9 and 22 to produce a fusion gene (bcr-abl) that gives rise to a constitutively activated Abl tyrosine kinase. This kinase led to the discovery of several small-molecule inhibitors, imatinib being the first and most successful of these. Resistance to imatinib results in some patients from Abl kinase point mutations. Overcoming imatinib resistance represents one of the biggest challenges facing clinicians in the modern management of CML. In this review, we discuss the current understanding of CML pathophysiology and mechanisms of imatinib resistance and how advancing this knowledge has led to the design of novel therapies in the area of blastic phase CML and Philadelphia chromosome-positive acute lymphoblastic leukemia with previous imatinib failure.
Question: What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?
bcr-abl

Context: The District of Keewatin was a territory of Canada and later an administrative district of the Northwest Territories.
Question: What was replaced District of Keewatin?
northwest territories