Final answer:
The primitive atmosphere of the early Earth likely did not contain oxygen. It consisted of water vapor, methane, ammonia, and carbon dioxide.
Step-by-step explanation:
The primitive atmosphere of the early Earth likely did not contain oxygen. According to scientific findings, the atmosphere of the primitive Earth consisted of water in the form of steam, methane, ammonia, and carbon dioxide. Oxygen only became abundant in Earth's atmosphere much later, after the evolution of photosynthetic organisms.