Use the following information to answer the questions below.
Paulinella chromatophora is one of the few cercozoans that is autotrophic,carrying out aerobic photosynthesis with its two elongated "cyanelles." The cyanelles are contained within vesicles of the host cell,and each is derived from a cyanobacterium,though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.
-The closest living relative of P.chromatophora is the heterotroph,P.ovalis.What type of evidence permits biologists to make this claim about relatedness?