Final answer:
Option e, which claims sexual reproduction reduces the chances of producing defective offspring, is not a hypothesized advantage of sexual reproduction. Instead, sexual reproduction is valued for creating genetic variation and enhancing population survival in changing environments, despite the potential for defective genes to be expressed.
Step-by-step explanation:
Disadvantages of Sexual Reproduction
The option which is not a hypothesized advantage of sexual reproduction is e. It reduces the chances of producing defective offspring. While sexual reproduction does indeed create genetic variation and helps in recombining advantageous alleles (b), as well as helps in removing deleterious genes from a population over time (c) and can increase resistance to parasites (d), it doesn't necessarily reduce the chances of producing defective offspring. In fact, due to the combination of genes from two different parents, there's the potential for harmful recessive genes to combine and express a phenotype in the offspring that might not be advantageous.
Sources of genetic variation in sexual reproduction such as crossing-over, independent assortment, and the random union of gametes create diverse phenotypes that may enhance the survival of a population in changing environments. Contrary to the claim in option e, sexual reproduction can sometimes lead to the expression of defective genes, although this might be balanced by the benefits of increased genetic diversity.