Why is it important for immigration and emigration to keep the genetics from inbreeding? plss help

What do animals wth echolocation have in common other than echolocation

All vaccination should(n’t) be mandatory! 1.at least 5 sentences explaining 2.why? 3.in the end summarize the sentence

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere, b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify, d)anaerobic bacteria kept thriving with more oxygen