How do jellyfish make it harder for other sea-creatures to live?

Because, they sting other fish with there shock.

Eukaryotic cells are theorized to have evolved from prokaryotes called the endosymbiotic theory. this explains that the most primitive eukaryotic cell engulfed a prokaryotic cell (by the process of phagocytosis) that is capable of cellular respiration and another prokaryotic cell that is capable of photosynthesis. these prokaryotic cells eventually became organelles and these organelles are the mitochondria and the chloroplast

Answer: the dna polymerase checks for errors in dna to prevent replication mistakes.
i hope this !