question:  Why is it important to watch the ones who don't become physically ill during the conditioning process?
context: "No specific destination," supplied the man as he punched a key on a small instrument, "Air-lock ahead and to your right. "Place your clothing in the receptacle provided and assume a stationary position on the raised podium in the center of the lock." Short of Gravitational conditioning, there is nothing to stop you from going to Terra." Your body is conditioned to a normal state of free fall, or at best to a state of acceleration." "You were ill, couldn't keep your balance, felt dizzy. It helps suppress certain physiological reactions to an entirely new set of conditions. They play an important part in our awareness of balance. Without gravity they act up for a time, then gradually lose function. Returning to gravity is rather frightening at first." During the days that followed, the psychologist seemed to Craig to become progressively more didactic. They were incredibly varied, even those that supported life. He had weathered difficult landings on worlds with rip-tide gravities, had felt the pull of the incredible star-tides imparted by twin and even triple star systems. He had been on Einstein IV, the planet of eight moons, and had felt the pulse of all eight of the satellites at once that no PON could completely nullify. But even if he could accept the psychologist's authority for the cumulative effect of a gravity system, he could not understand the unspoken warning he felt underlying all that the man said. You agreed that you could not decide that for me and that my decision is logical. On the eighth day, two attendants, who showed the effects of massive doses of PON to protect themselves from the centrifugal force, had to carry a man out of the tank. Many others asked to be removed, begged to be allowed to withdraw their resignations. "How ... how do they know when you ought ... to come out?" "Blood pressure. "Can't they ... drop it down continuously?"
output:  Their bodies' familiarity with gravity naturally makes them suspicious
options:  They could be tapped as leaders for Freedomite missions  It is a sign that they are deviant extraterrestrials  Their bodies' familiarity with gravity naturally makes them suspicious  Their bodies may naturally produce paraoxynebutal