Fish lay thousands of eggs in one reproductive cycle. what are some factors that prevent the majority of these from developing into fish that then reproduce on their own

Fish are abundant but through evolution they have been made to lay a lot of eggs. This accounts for one thing, survival of the fittest. Darwinism theory of Natural Selection.

Organism, organ system, organs, tissue, cells

Carbon-14 has a half-life of 5,730 years and most igneous rock is older than that.