Oh, I see what you are saying! So, part of the issue is that the dates are disconnected from the text divs. So, when the screen responds, the text drops down below the list of dates. There is no organizational grouping between the two, if you will.
In following your current architecture, you can structure it with the text and the date in the same div, like this:
<div id="block1">1942 Born Cassius Marcellus Clay, Jr., on Jan. 17, in Louisville, Ky., to Odessa and Cassius, Sr. (a sign and mural painter).</div>
To give more space between the date and the line of text, you can always create a span class and then give it a text-indent property. Then, assign that span class to the other divs.
As i’m sure you are learning, there are many ways to do this. You can also treat each div as a column in a grid and use bootstrap to help with the css/grid structure.
I hope this helps some! Let me know if you have any questions.