Two gametes, each carrying a mutant recessive allele for a different gene/enzyme in the adenine biosynthetic pathway, come together to form a diploid embryo. The individual derived from this embryo will display a:______.
a. lethal phenotype in media lacking adenine supplementation.
b. wild-type phenotype, capable of synthesizing adenine.
c. a weak adenine requirement for survival (intermediate phenotype).
d. a profound defect in adenine synthesis as two enzymes are missing.
e embryonic lethality.
f. co-dominant recessive mutant, incapable of synthesizing adenine synthetic lethal interaction.