Answer:
Blue and red
Explanation:
Action spectrum is the region of light that is utilized for photosynthesis by photosynthetic organisms.
According to several research, the rate of photosynthesis in green plants is highest in red region of light, followed by blue region.
If Halobacterium's photosynthetic action spectrum is the opposite of green plants and photosynthetic organisms, it means the rate of photosynthesis in Halobacterium will be highest in blue light, followed by red.
The answer is blue and red.
