Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Exposition
"Where Are We Going, Dad?"
The story begins with Nick travelling to a place that he presumably has never been to before, about to witness something that he presumably has never witnessed before. New place + new experiences = ensuing shenanigans.
Rising Action
"Oh, Daddy, can't you give her something to make her stop screaming?"
That new experience we just mentioned? Yeah, turns out to be less than pleasant and exciting for poor little Nick than we all might've hoped. This is when the action starts to rise. He spends most of the time trying not to look at what his father is doing, even though that was the whole point of bringing him along.
Climax
An Unexpected Turn
Just when we think everything is over and done with and all neatly sewn up (pun intended), we discover the husband's suicide. Everything that was fine is suddenly far from fine, and the whole lesson about where babies come from has been turned on its head.
Falling Action
"Do many men kill themselves, Daddy?"
Now Nick's father is left with a task somehow more difficult than doing a Caesarian with a jack-knife and explaining the facts of life to his kid: he has to explain the facts of death and suicide. It's like the depressing side of the birds and the bees. On Nick's part, he now has to process this new information. This is one boat ride we're super happy not to be on.
Resolution
No More Questions
The story's resolution comes in the very last line of the story. Before, Nick was still asking his father questions, so still acting as though his father had some sort of knowledgeable authority. But in the last line, Nick comes to his own conclusion about death, which still feels like this impossibility.