Question

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
a. mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.
b. mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.
c. the products of photosynthesis could not be metabolized without mitochondrial enzymes.
d. all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.
e. without mitochondrial CO2 production, photosynthesis could not occur.

Answer 1

The right answer is D.

Mitochondria is a cellular cytoplasmic organelle that plays an essential role in respiratory and energetic phenomena. It is present in eukaryotic cells (with exception).

Plastids are plant organelles that often contain a pigment. This is the site of photosynthesis. It is present only in certain eukaryotes.

The fact that the mitochondria is better answered justifies the hypothesis that mitochondria have endosymbiosis before plastids.