instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
What is one example of hydrogen cations?, Context: To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium ion" (H3O+). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to H9O+4. Other oxonium ions are found when water is in acidic solution with other solvents.
answer:
hydronium ion

question:
What was the final act by politicians that angered the plebeians before seceding?, Context: By 287 BC, the economic condition of the average plebeian had become poor. The problem appears to have centered around widespread indebtedness. The plebeians demanded relief, but the senators refused to address their situation. The result was the final plebeian secession. The plebeians seceded to the Janiculum hill. To end the secession, a dictator was appointed. The dictator passed a law (the Lex Hortensia), which ended the requirement that the patrician senators must agree before any bill could be considered by the Plebeian Council. This was not the first law to require that an act of the Plebeian Council have the full force of law. The Plebeian Council acquired this power during a modification to the original Valerian law in 449 BC. The significance of this law was in the fact that it robbed the patricians of their final weapon over the plebeians. The result was that control over the state fell, not onto the shoulders of voters, but to the new plebeian nobility.
answer:
the senators refused to address their situation

question:
Why did remaining engines have to compensate?, Context: The delay in the CSM caused by the fire enabled NASA to catch up on man-rating the LM and Saturn V. Apollo 4 (AS-501) was the first unmanned flight of the Saturn V, carrying a Block I CSM on November 9, 1967. The capability of the Command Module's heat shield to survive a trans-lunar reentry was demonstrated by using the Service Module engine to ram it into the atmosphere at higher than the usual Earth-orbital reentry speed. This was followed on April 4, 1968, by Apollo 6 (AS-502) which carried a CSM and a LM Test Article as ballast. The intent of this mission was to achieve trans-lunar injection, followed closely by a simulated direct-return abort, using the Service Module engine to achieve another high-speed reentry. The Saturn V experienced pogo oscillation, a problem caused by non-steady engine combustion, which damaged fuel lines in the second and third stages. Two S-II engines shut down prematurely, but the remaining engines were able to compensate. The damage to the third stage engine was more severe, preventing it from restarting for trans-lunar injection. Mission controllers were able to use the Service Module engine to essentially repeat the flight profile of Apollo 4. Based on the good performance of Apollo 6 and identification of satisfactory fixes to the Apollo 6 problems, NASA declared the Saturn V ready to fly men, cancelling a third unmanned test.
answer:
Two S-II engines shut down prematurely