Teacher: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 (", ").
Teacher: Now, understand the problem? Solve this instance: Paragraph- Sent 1: Surely, you have noticed the tall poles along the roadside.
Sent 2: Do you know what is on top of those poles?
Sent 3: Thats right, wires that carry electric current.
Sent 4: These wires carry electric current to your home.
Sent 5: But what is electric current?
Sent 6: Electric current is actually the flow of electrons.
Sent 7: You may recall, an electron is the outer-most particle in an atom.
Sent 8: They have a negative charge.
Sent 9: Electricity is the continuous flow of these particles.
Sent 10: Electrons are able to move through wires.
Sent 11: Their speed can even be measured.
Sent 12: The SI unit for electric current (or speed) is the ampere (A).
Sent 13: Ampere is often shortened to amp.
Sent 14: Electric current may flow in just one direction, or it may keep reversing direction.
Sent 15: Direct current (DC) flows in only one direction.
Sent 16: Direct current is what is used in devices like flashlights.
Sent 17: Alternating current (AC) flows in two directions.
Sent 18: This is the type of current that flows into your home through wires. 
Question: What is on top of the poles on the roadside?.
Student:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
1, 2, 3.