Ribosome Types in Cellular Structures

Steps:

• List structures in order: chloroplast, eukaryotic cytoplasm, prokaryotic cell, mitochondrion.
• Recall 70S ribosomes in prokaryotes and endosymbiotic organelles (chloroplasts, mitochondria); 80S in eukaryotic cytoplasm.
• Assign types: chloroplast (70S), eukaryotic cytoplasm (80S), prokaryotic cell (70S), mitochondrion (70S).
• Match sequence 70S, 80S, 70S, 70S to option B.

Why B is correct:

• It sequences the ribosome types accurately for prokaryotic-origin structures (70S) versus eukaryotic cytosol (80S), per endosymbiotic theory.

Why the others are wrong:

• A: Includes descriptive labels instead of a plain type sequence for the row.
• C: Incorrectly assigns 80S to chloroplasts and mitochondria, which are 70S.
• D: Falsely claims all 80S, ignoring prokaryotic and organelle distinctions.

Final answer: B