Yes, the box where you insert text. It's got two tabs up left, "Visual" and "HTML". Visual is where you see approximately what you'll get in the post; HTML is where you see the code for it.
At the moment the code of your latest post goes like that:
<div id="_mcePaste" style="left:-10000px;width:1px;position:absolute;top:0;height:1px;">There is a food faster than “fast food!” It’s fruit! How easy is it to run into a grocery store for instant gratification with a bag of grapes, a bunch of bananas or a pint (or two) of blueberries?</div>
<div id="_mcePaste" style="left:-10000px;width:1px;position:absolute;top:0;height:1px;">This is a very simple solution to eating healthy that we forget to take advantage of. We’ve been misled to think that you have to leave fruit for a treat or dessert, that it can’t be a meal. Well it’s true that one piece of watermelon or a handful of grapes is not a meal. But a half watermelon is quite satisfying. A pound of grapes are also satisfying. A four pound container of fruit from Costco is quite enough for two to share.</div>
Everything included between all the "<" and the ">" must go: that's the junk code that prevents you from formatting your text. Do as I suggested in my previous post, and then you'll be able to create paragraph breaks the normal way, i.e just by hitting return.
For future posts, if you continue pasting from another source, do it via the "Paste as plain text" button of the editor.
As for the function of all the buttons, see here: