Please help. i do not know the definition to these will anybody help me.

How did the research presented in the article affect scientists' understanding of the evolution of eukaryotes

Hydrilla (hydrilla verticillata) is an invasive aquatic plant and one of the most serious aquatic pests in florida. hydrilla has already been introduced to hundreds of bodies of water throughout florida, hydrilla is difficult to control because it grows rapidly and survives in many different water depths and conditions. hydrilla • describe how hydrilla affects native plant and animal species. include both a biotic and an abiotic limiting factor. • suggest one biotic and one abiotic recommendation that could slow the spread of hydrilla

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.