Final answer:
The most immediately affected population by the removal of lizards would be one that relies on them for food or is impacted by their ecological role, such as centipedes if they are a prey species, or sedges if lizards help control insect pests.
Step-by-step explanation:
The population that would be most immediately affected by the would typically be a population that directly depends on lizards for food or is indirectly affected by their elimination. Without specific information about the diet and ecological relationships between the listed organisms, it is difficult to provide a definitive answer. However, if lizards are a primary food source for centipedes, the removal of lizards from the ecosystem could greatly impact the centipede population.
If the lizards control insect populations that are pests to sedges, then sedges could be indirectly affected as well. Algae would be less likely affected as they are not part of a terrestrial lizard's diet or ecosystem impact. Ants could potentially be affected if lizards prey on them or compete with them for food, but this impact would not be as immediate as that on the prey of lizards like centipedes.