Final answer:
The claim that the okapi has a back that slopes upward is false. The okapi has a downward sloping back, similar to that of its relative, the giraffe. The giraffe's long neck is an adaptation to reach foliage in tall trees, refuting the idea that stretching alone leads to longer necks.
Step-by-step explanation:
The statement that the okapi has a back that slopes upward is false. Okapis actually have a distinctive body shape with a back that slopes downward, from the rump to the shoulders. This body shape is somewhat similar to that of the giraffe, to which the okapi is a close relative. The giraffe's long neck, which is a result of generations of natural selection, allows it to reach high foliage on trees, making it an observation relevant to hypothesis 2B which mentioned that the only available food was on tall trees. However, it is important to clarify that, according to the theory of evolution, animals like the giraffe did not simply stretch their necks to become longer over time as mentioned in scenario C, but rather, giraffes with naturally longer necks were more likely to survive and reproduce, passing this trait on to their offspring.