Final answer:
Neither DCMU nor sodium azide directly inhibit the flagellar motion, but both can indirectly inhibit motility in Chlamydomonas by hindering energy production processes which are critical for movement.
Step-by-step explanation:
Chlamydomonas, a mobile organism using two flagella for movement, is known to be susceptible to certain chemicals that can inhibit its motility. DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a chemical that inhibits photosynthesis by blocking electron transport in the photosystem II. While DCMU is not directly known to inhibit motility in Chlamy, it could indirectly affect movement by reducing the energy available for flagellar motion. Sodium azide is a potent inhibitor of cytochrome c oxidase in the electron transport chain, and thus, it inhibits aerobic respiration. By inhibiting respiration, sodium azide would reduce ATP production, which is needed for flagellar movement, consequently leading to inhibited motility in Chlamydomonas.