Two species have a relationship with one another in an ecosystem. suppose one of these two species goes extinct. which type of relationship did the two have if the surviving species population increases after the other goes extinct?

Given that both the extinct and the surviving species had a relationship with one another in the ecosystem, and that there was an increase in the population of the surviving species after the other goes extinct. It means that the extinct species was a parasite in a parasitic relationship with the surviving species.