Not supported, because the author doesn’t suggest that physicists failed to realize atoms could be split due to any neglect (meaning, disregard) of earlier theoretical developments. Meitner may have made a crucial theoretical connection that allowed physicists to realize the significance of the neutron bombardment experiments, but this doesn’t imply that physicists besides Meitner neglected anything. There’s a difference between, on the one hand, failure to realize the significance of earlier developments and their relationship to one’s own experiments, and on the other hand, the neglect of earlier developments. In addition, we can intepret Meitner as part of the physics community of the 1930s, which would suggest that the community actually did not neglect earlier developments; Meitner’s realization of the theoretical connection between the neutron bombardment experiments and the splitting of atoms would be part the achievements of the 1930s physics community.

Not supported, because we have no evidence that the physicists “reevaluated” calculations. We know that some theoretical physicsts had produced calculations that showed “in principle it should be possible to break atoms apart.” But we’re never told any other physicists changed their evaluation of these calculations. Perhaps other physicists didn’t realize the significance of these calculations, but that doesn’t imply anyone reevaluated these calculations.

Anti-supported. The author indicates that physicists did identify the by-products of neutron bombardment of uranium: barium and technetium. Although Fermi and others didn’t identify those by-products, other physicists of the 1930s did.

Not supported, because the author never compares the ease with which uranium atoms can be split to the ease of splitting other kinds of atoms.

Stated. The author states that one reason Fermi and other physicists didn’t discover the by-products of neutron bombardment of uranium is the dangers of working with radioactive material. This indicates that the physicists were aware of the dangers.