The correct responses regarding how crossing over can benefit eukaryotic organisms are:
b. Crossing over increased genetic variation- diversity.
d. Crossing over results in the production of genetically unique organisms.
Options a and c do not correctly represent the benefits of crossing over in eukaryotic organisms. Option a is incorrect because crossing over does not create diploid cells from haploid cells; it occurs during meiosis and contributes to genetic variation in haploid gametes. Option c, while highlighting that crossing over requires energy and can lead to errors, does not describe a benefit.