Riddle Me THIS! in BookThree: Flight Log 2016

I was crafting a riddle this morning trying to get the answer to be both perceptible but not easy. Then, after I finished, I remembered an easier way to get there. Below are both riddles (they have the same answer)… which one do you like best?

(1) Though most popular, I am not in this group of words. How odd! What am I?

(2) I am in everywhere and nowhere. I am in the earth, but I am not in dirt. I am in the heart, but not in blood. What am I?