Final answer:
First Light exhibits high scalability due to its substantial revenue increase coupled with low additional costs upon expanding to new markets.
Step-by-step explanation:
In the scenario where First Light, an online news portal, has extended its services to North and South America and has seen a substantial increase in revenues at very low additional costs, the organization is most likely to have high scalability. \
Scalability refers to the capability of a business to grow and manage increased demand without a significant increase in costs. Since First Light was able to expand its services and increase its revenues without incurring high additional costs, it indicates that the business model is such that it can handle growth efficiently, thus showcasing high scalability.