The writer mentions heart and circulation because they are the most important structures in the human body
since students have great difficulty understanding their relationship
in order to illustrate the extent to which students should be taught human biology
as these parts of the body are frequently damaged by excessive exercise
as examples of the areas in which health education is lacking
We can infer from the passage that by training the heart people can expect to live much longer
we become capable of doing more complicated activities
the lungs' function in the partnership becomes virtually redundant
people can easily survive with a single lung
we can prevent the lungs from overworking
According to the passage, health education in schools should be detailed
functional
anatomical
structural
physiological
132 APOLLO 13 Apollo 13 was an American space mission in 1970, part of the Apollo program. It was intended to be the third mission to land on the Moon.
An oxygen tank in the Service Module exploded while the spacecraft was on its way to the Moon, requiring the mission to be aborted: the Moon landing was cancelled and only a single pass around the Moon was made. Considerable ingenuity under extreme pressure was required from both the crew and the ground controllers to figure out how to jury-rig the craft for the crew's safe return, with much of the world watching the drama on television.
Reentry into the Earth's atmosphere required the unusual step of undocking the lunar module, which had been retained for the flight back to Earth, in addition to the separation of the damaged service module. The lunar module had remained attached to the spacecraft to provide emergency propulsion and life support. The crew returned unharmed to the Earth.
In the wake of the near-disaster, NASA appointed a review board under the leadership of Edgar M. Cortright, director of Langley Research Center, to investigate the Apollo 13 accident. After some three months of study, the cause of the explosion was traced to two inadequate thermostatic switches in an oxygen-tank heater assembly. Dysfunction of the switches under load caused overheating that led to an insulation fire, and the subsequent blast tore a side panel from the service module and disabled the fuel cells. Other defects in manufacture and in testing procedures were also found. Further Apollo flights were delayed until 1971 so that modifications could be made to prevent similar incidents.
Jim Lovell, who was one of the crew members, wrote a book about the mission, Lost Moon, which was later turned into a successful movie, "Apollo 13", starring Tom Hanks.
