Which statement regarding porphyrin synthesis pathways is CORRECT?
A. The succinyl-CoA/glycine porphyrin pathway is used by all bacteria, photosynthetic eukaryotes, and archaea.
B. The porphyrin biosynthetic pathways are unified at the step of 5-aminolevulinic acid.
C. The glutamate porphyrin pathway is used by all non-photosynthetic eukaryotes and alpha-proteobacteria.
D. There is very little conservation of porphyrin synthesis pathways between eukaryotes, bacteria, and archaea.
Answer: B
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