Answer:
Energy
Explanation:
An energy pyramid shows the amount of energy available at each feeding level in an ecosystem.
I believe the answer is head-on and port (left). The side lights are usually visible to vessels approaching from the front or the side. The red light usually indicates a vessel's port (left) side while the green light indicates a vessel's starboard (right) side. These lights ensure that there is safety at night as the vessels navigate.
This is true. Hope this helps.