Why did the authors choose to look for the rubisco gene in their core samples?

Question

Quizplus · Accepted Answer

Rubisco is a key enzyme used in photosynthesis by all plants, and therefore looking for the rubisco gene in the core samples would provide information about the presence and productivity of photosynthetic organisms in the environment. A, B, and E are incorrect because they are not relevant to the role of rubisco in photosynthesis. C is incorrect because while rubisco is involved in respiration to an extent, its primary function is in photosynthesis.

Why Did the Authors Choose to Look for the Rubisco