Answer:
Option A, A focus on individual species is cheaper than protecting entire ecosystems
Step-by-step explanation:
The Endangered Species Act (ESA), 1973 provides a legislative backing to all such programs that are intended to conserve threatened and endangered plants and animals and their habitat.
The major objective was to maintain the integrity of the ecosystem by conserving its diversity. However, it would be difficult to carry out a mass preservation program for the entire ecosystem , hence it was considered necessary to first focus on all such species which may get extinct if not taken care of today
Hence, option A is correct