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.

Q: Context: One of the primary criticismes of vestibular schwannoma (VS) radiosurgery is that the risk of surgical morbidity is increased for patients whose tumor progresses after the procedures. We reviewed the French experience of operated patients after failed Gamma Knife radiosurgery. From July 1992 to January 2002, 25 out of the 1000 treated patients underwent another treatment procedure for a gamma knife failure. Excluding the NF2 patients, 21 patients have been operated and the present study shows the data collected for 20 of them. In order to analyze the difficulties observed during the surgery, a questionnaire was filled by the surgeons. The mean interval between radiosurgery and removal was 36 Months, from 10 to 83 Months. The mean increase in Volume was 559% (37 to 3036%, median 160%). Evolution of the Koos grading was found from 8 grade II, 10 grade III et 2 grade IV to 10 grade III and 10 grade IV. Patients have been operated for radiological tumor growth in 7 cases and for clinico-radiological evolution in 13 cases. In 9 cases, the surgeon considered that he had to face unusual difficulties mainly because of adhesion of the tumor to neurovascular structures. Tumor removal was total in 14 cases, near total in 4 cases and subtotal in 2 cases. One case of venous infarction was noticed at the second day following surgery responsible of hemiparesis and aphasia that gradually recovered. At last follow-up examination, facial nerve was normal (House and Brackmann grade I and II) in 10 cases while it was a grade III in 7 cases and grade IV and V in 3 cases. We recommend that the decision for surgical removal of growing vestibular schwannoma after Gamma Knife treatment should be done after a sufficiently long follow-up period. Our results show that the quality of removal and of facial nerve preservation might be impaired by radiosurgery in half of cases. However these results do not support a change in our policy of radiosurgical treatment of small to medium size vestibular schwannoma.
Question: Which disease can be categorized using the Koos grading system?

A: vestibular schwannoma
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Q: Context: DNA must replicate (copy) itself so that each resulting cell after mitosis and cell division has the same DNA as the parent cell. All these cells, the parent cell and the two new daughter cells, are genetically identical. DNA replication occurs during the S phase (the Synthesis phase) of the cell cycle, before mitosis and cell division. The base pairing rules are crucial for the process of replication. DNA replication occurs when DNA is copied to form an identical molecule of DNA. The general steps involved in DNA replication are as follows: 1. The DNA helix unwinds like a zipper as the bonds between the base pairs are broken. The enzyme DNA Helicase is involved in breaking these bonds. 2. The two single strands of DNA then each serve as a template for a new stand to be created. Using DNA as a template means that on the new strand, the bases are placed in the correct order because of the base pairing rules. Recall that A and T are complementary bases, as are G and C. As a template strand is read, the new strand is created. If ATGCCA is on the "template strand," then TACGGT will be on the new DNA strand. The enzyme DNA Polymerase reads the template and builds the new strand of DNA. 3. The new set of nucleotides then join together to form a new strand of DNA. The process results in two DNA molecules, each with one old strand and one new strand of DNA. This process is known as semiconservative replication because one strand is conserved (kept the same) in each new DNA molecule ( Figure 1.1). DNA replication occurs when the DNA strands unzip, and the original strands of DNA serve as a template for new nucleotides to join and form a new strand.
Question: what is the first step in dna replication?

A: the dna helix unwinds like a zipper.
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Q: Context: The movie starts off with archive black-and-white footage of the Nazi's atrocities on the Jews across Europe. The focus shifts to West Belarus, where Nazi SS soldiers, under the command of Bernicki, the Belarussian Police Captain, are busy "sanitizing" a village, killing half the people and abducting the rest. Zus Bielski (Liev Schreiber) and his brother, Asael (Jamie Bell), watch helplessly from the forest. Once the Germans have left, they run to the village and are devastated to find their father dead. They go to their house and find their youngest brother, Aron (George MacKay), cowering under the floorboards in the closet. They take him with them to the forest.In the Lipiczanska Forest, Zus tells a weeping Asael to get a hold of himself. As they sleep, their eldest brother, Tuvia Bielski (Daniel Craig), walks up to them and wakes them up. He first admonishes Asael for not being alert, then embraces him and Aron emotionally. Zus and Tuvia have a rather curt reunion. As they walk into the forest, Zus tells Tuvia that his wife and child are hiding in a village. At night, they discuss their options. The police are after them, however they are safe in the woods. They talk about Bernicki. A friend, Koscik has a gun which they can borrow. Next morning, Aron stumbles across some other Jewish refugees in the forest. He brings them back to his brothers. One of them is a young child, mortally wounded. Unfortunately, they can't save her. As her parents grieve, Zus tells Tuvia that they can't support these people. Tuvia says he'll ask Koscik for food and his pistol.In the nearby village, Konstanty 'Koscik' Kozlowski, their friend and a secret Jew-sympathizer, lets Tuvia inside and gives him food, drink and his pistol, with only 4 bullets. Seeing a police car coming towards the house, Koscik hides Tuvia in the barn, along with some other Jews. It's Bernicki and his sons, who Koscik welcomes warmly. Bernicki talks about his Jew-hunting exploits. Bernicki talks about having killed the Bielskis' father and is now after the sons. He tells Koscik to keep his eyes open and leaves. After they're gone, Koscik gives Tuvia food and drink and asks him to take the Jews from his barn. Tuvia confirms that Bernicki and his sons were responsible for his parent's deaths. He then takes the other Jews and goes into the forest.As they walk into the forest, one of the Jews, an elderly man named Shamon Haretz, Tuvia's old school-teacher, talks to him about his experiences. Tuvia brushes him off. At the campsite, the food is being passed around, with each person taking a small morsel so the others can have some. Zus is upset that Tuvia brought more mouths to feed. Tuvia tells him that it was Bernicki who killed their parents. That night, he goes to Bernicki's house, where he is having dinner with his wife and two sons. Tuvia bursts inside and holds them at gunpoint. He asks them if he knows who he is and why he's there. Terrified, Bernicki says he did as ordered. Tuvia orders him to his knees. Bernicki's sons jump up to their father's aid, but Tuvia shoots them dead. He then shoots Bernicki dead. Bernicki's hysterical wife pleads with Tuvia to kill her as well. Leaving her alive and grief-stricken, he leaves.The next morning, Tuvia tells Zus he killed Bernicki and his sons. They decide to move deeper into the woods. Tuvia brings over more Jews, much to Zus' displeasure. One of them is Isaac Malbin (Mark Feuerstein). The refugees start building makeshift houses in the woods. After almost hitting Zus with a log, Isaac confesses that he's an intellectual, not a carpenter. A refugee introduces Tuvia to his "forest wife". Tuvia congratulates them, a bit unsurely. Just then, two men burst into the scene, one of them holding a rifle, while
Question: Where did the brothers flee?

A:
into another part of the woods.
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