The best answer to the question states above is letter C.<span> A short observation period.
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<span> A scientist's primary concern in a clinical trial is the patient's safety, there fore short observation </span><span>decreases the reliability of results from a clinical trial</span>
it would affect the growth curves because you see if a bacteria affects predators (that hunt and eat preys) the number of predators would decrease as they would be killed by the infection
Less predators means more preys as they aren’t hunted down as much so they growth curve for preys would be positive while for predators it would be negative
