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.

The correct answer is option D

It has been proposed that chloroplast evolved from Cyanobacteria because they performed photosynthesis.

Chloroplast is the main site site for the process of photosynthesis found in the plant cell.

Photosynthesis is the process by which the cyanobacteria made food ( glucose) for their survival and released oxygen into the environment.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.