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 (", ").
Input: Paragraph- Sent 1: The center of an atom is held together by powerful forces.
Sent 2: This gives them a huge amount of stored energy.
Sent 3: This type of energy is called nuclear energy.
Sent 4: This energy can be released and used to do work.
Sent 5: This happens in nuclear power plants where they split apart the nucleus of an atom.
Sent 6: This splitting apart is called nuclear fission.
Sent 7: Another type of nuclear energy happens in the Sun.
Sent 8: Here the atoms nuclei are not split apart.
Sent 9: Instead, the nuclei of the atoms are fused, or joined together.
Sent 10: This process is called nuclear fusion.
Sent 11: Some of the suns energy travels to Earth.
Sent 12: This energy from nuclear fusion warms the planet and provides the energy for photosynthesis. 
Question: Does the atoms nuclei in the Sun split apart?.
Output:
7, 8.