Question

what observation led researchers to propose that chloroplasts evolved from cyanobacteria?
both produce proteins.
both contain mitochondria.
both provide structure to cells.
both perform photosynthesis.

Explanation:

Chloroplasts are organelles in plant cells that perform photosynthesis. Cyanobacteria are prokaryotes that also perform photosynthesis. The shared ability to carry out photosynthesis is a key similarity. Proteins are produced by many cell components (not unique to these two). Chloroplasts and cyanobacteria do not contain mitochondria (mitochondria are another organelle). Chloroplasts do not provide structure to cells (cell walls or cytoskeleton do that).

Answer:

D. Both perform photosynthesis.