TASK DEFINITION: You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").
PROBLEM: Paragraph- Sent 1: Electric current cannot go through empty space.
Sent 2: Electricity needs something to flow through.
Sent 3: Electricity cannot flow through all materials.
Sent 4: Some materials resist the flow of electricity.
Sent 5: Some materials let electricity pass through easily.
Sent 6: Scientists classify these into two groups.
Sent 7: These groups are called conductors and insulators.
Sent 8: Materials that allow electrons to flow freely are called electric conductors.
Sent 9: Electricity is able to race through these materials.
Sent 10: Copper, aluminum, and steel are good conductors.
Sent 11: Materials that resist the flow of electricity are called electric insulators.
Sent 12: Instead of racing, the current may travel in slow motion, if at all.
Sent 13: Wood, rubber, and plastic are examples of electric insulators.
Sent 14: You probably know that electric wires are made of metal.
Sent 15: They typically have a rubber or plastic coating.
Sent 16: Do you know why?
Sent 17: Metals are good electric conductors.
Sent 18: They offer little resistance to electricity.
Question: Do metals offer much resistance to electricity?.

SOLUTION: 17.

PROBLEM: Paragraph- Sent 1: What if two children push a swing at the same time?
Sent 2: Would the swing go higher?
Sent 3: Yes, together their force would be more.
Sent 4: It is common for forces to be combined.
Sent 5: Most objects on Earth have at least two forces acting on them.
Sent 6: Do you know what one of them is?
Sent 7: Of course, that force is gravity.
Sent 8: How many forces do you have on you right now?
Sent 9: Gravity pulls you down toward the center of Earth.
Sent 10: Your legs exert a downward force.
Sent 11: They hold you up against the pull of gravity.
Sent 12: Consider the example in Figure 1.3.
Sent 13: A book is resting on a table.
Sent 14: Gravity pulls the book downward.
Sent 15: It has a force of 20 newtons.
Sent 16: At the same time, the table pushes the book upward.
Sent 17: Its force is also 20 newtons.
Sent 18: The table opposes the pull of gravity.
Question: What part of one's body can hold them up against the force of gravity?.

SOLUTION: 9, 10, 11.

PROBLEM: Paragraph- Sent 1: '' The Octopus , '' a masked crime lord , is bent on crippling the nation with a wave of terror .
Sent 2: He starts with the transportation system and then moves onto industry .
Sent 3: He demands tribute from railroad magnates and other captains of industry .
Sent 4: Richard Wentworth , an amateur criminologist who is friendly with the police , is secretly '' The Spider , '' a masked vigilante equally determined to wipe the Octopus and his gang off the face of the earth .
Sent 5: Pleasant and smiling in civilian life , Wentworth is often ruthless as the Spider , slinging two guns against the public enemies who attack him .
Sent 6: Wentworth also masquerades as affable underworld lowlife Blinky McQuade .
Sent 7: Disguised as McQuade , Wentworth can infiltrate gangland at the hired-gun level and keep current on the gang 's plans .
Sent 8: The only people who know Wentworth 's other identities are his assistants Jackson and Ram Singh , his butler Jenkins , and his fianc e Nita .
Sent 9: The Octopus was a villain in a single issue pulp believed to have been written by Norvell Page who wrote most of The Spider pulp stories .
Sent 10: He is garbed completely in white and is only ever seen sitting in a chair .
Sent 11: Unlike the pulps , The Spider is garbed in a lightweight full length costume with web-like markings on it which resemble Spiderman 's costume .
Sent 12: The serial follows the standard formula of fights , shoot-outs , Wentworth 's friends being kidnapped at various times and having to be rescued .
Sent 13: Each chapter ends with The Spider or his friends in deep trouble , often about to be killed , but the effect is spoiled by a trailer for the next episode which shows them in full health and fighting the villains .
Question: What is Wentworth's job that allows him to maintain a friendly relationship with the police?.

SOLUTION:
4.