Brony: Sorry it took so long to respond. It’s basically what Popa said to SecularFrummy, though I obviously get more detailed and in-depth. It works with “long day”, though long day isn’t necessary. Because once you believe that G-d created the world, He could have done it however He wants. So He did it with a system of interconnectedness and a world that looked as if it had developed for billions of years. Why would He do that? Modern medicine is the answer. Hashem gave us the world that He did so that in this day and age we can have the medicine and technology that we are meant to have at this point of our historical development.
Honestly, the fact that the Torah says we were down to 9 humans less than 5000 years ago has stronger questions from science than the first few Perakim of B’reishis do (though, of course, these are answerable as well).