1. The problem asks which model correctly shows the conversion of molecules by chloroplasts and mitochondria. 2. Important biological facts: - Chloroplasts perform photosynthesis: they take in $\mathrm{CO_2}$ and $\mathrm{H_2O}$, use light energy to produce $\mathrm{C_6H_{12}O_6}$ (glucose) and release $\mathrm{O_2}$. - Mitochondria perform cellular respiration: they take in $\mathrm{C_6H_{12}O_6}$ and $\mathrm{O_2}$, convert them into $\mathrm{CO_2}$, $\mathrm{H_2O}$, and produce ATP (energy). 3. Step-by-step analysis of each model: - Model A: Shows $\mathrm{CO_2}$ and $\mathrm{C_6H_{12}O_6}$ going to chloroplast, which is incorrect because chloroplasts produce glucose, not consume it. - Model B: Shows $\mathrm{H_2O}$ and $\mathrm{CO_2}$ going to chloroplast, $\mathrm{O_2}$ to mitochondrion, and mitochondrion producing ATP, which matches biological processes. - Model C: Shows glucose going to mitochondrion (correct), $\mathrm{H_2O}$ and $\mathrm{O_2}$ to chloroplast (incorrect, chloroplast produces $\mathrm{O_2}$), and $\mathrm{CO_2}$ to ATP (incorrect). - Model D: Shows $\mathrm{H_2O}$ to ATP (incorrect), $\mathrm{O_2}$ to chloroplast (incorrect), and $\mathrm{CO_2}$ to glucose (incorrect direction). 4. Therefore, Model B correctly represents the molecular conversions by chloroplasts and mitochondria. Final answer: Model B