Question

where do the krebs cycle and the electron transport chain occur?
in the chloroplasts
in the cytoplasm
in the mitochondria

Explanation:

The Krebs cycle occurs in the mitochondrial matrix and the electron - transport chain occurs in the inner mitochondrial membrane. So both processes occur in the mitochondria. Chloroplasts are involved in photosynthesis, and the cytoplasm is where glycolysis occurs (not the Krebs cycle and electron - transport chain).

Answer:

in the mitochondria