Critical Reasoning

Some types of organisms originated through
endosymbiosis, the engulfing of one organism by
another so that a part of the former becomes a
functioning part of the latter. An unusual
nucleomorph, a structure that contains DNA and
resembles a cell nucleus, has been discovered within
a plant known as a chlorarachniophyte. Two versions
of a particular gene have been found in the DNA of
this nucleomorph, and one would expect to find only
a single version of this gene if the nucleomorph were
not the remains of an engulfed organism’s nucleus.

Which one of the following is most strongly
supported by the information above?

(A) Only organisms of types that originated
through endosymbiosis contain
nucleomorphs.

(B) A nucleomorph within the chlorarachniophyte
holds all of the genetic material of some
other organism.

(C) Nucleomorphs originated when an organism
endosymbiotically engulfed a
chlorarachniophyte.

(D) Two organisms will not undergo endosymbiosis
unless at least one of them contains a
nucleomorph.

(E) Chlorarachniophytes emerged as the result of
two organisms having undergone
endosymbiosis.

OA TBA