Competition is most likely to occur between which two organism

Competition is most likely to occur between two organisms. When the organisms interfere with each others resource or when organisms interfere with each others reproduction which will cause the others life to be in short or danger.

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

Wow that a lot of text for my tiny so i no wanna answer