Final answer:
Boats should leave the green marks with odd numbers on the starboard side of the boat when entering a US harbor from the sea.
Step-by-step explanation:
The green marks with odd numbers should be left on the starboard side of the boat when entering a US harbor from the sea. In the US, the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) System B is followed. According to this system, green marks are placed on the starboard side of the channel when entering a harbor.