She buys a stethoscope. If her daughter is not human, she would like to know by just what measure - how fast is her heartbeat in comparison to a normal human's? It's not pumping blood, obviously - does she even have one?
"Astrid, sweetie, can I try a thing?" she asks, stethoscope in hand.
"This is a stethoscope," explains Lynn, showing the item to Astrid. "It helps you hear things you can't normally hear without help - you can play with it, if you like, but I'm - going to listen to you, check for something."
Lynn tests it on herself, to be sure that it works.
Thump, thump.
Right then. Astrid is not human.
"All right, dear - you know I love you no matter what, right?"
Pause. "I have no idea what you are, but I love you all the same. Okay?"
She offers up the stethoscope.
Astrid listens to Lynn, and to herself. "I don't thump," she confirms. "So I'm not an animal?"
"There are a few animals that walk on two legs, but none that I know of that look like they're human."
"But I'm not an animal, what's an not-an-animal that looks like a human?"
"I doubt it, because there only being one of something doesn't make sense. You had to come from something, somewhere. But I don't know where the others are."
"Because of the basket, and also because things don't - appear randomly. Especially living things, which you obviously are. Trees come from seeds, birds come from eggs, microscopic cells come from cell divisions."
"Maybe I came from an egg. Tiny tiny Astrid hatching from an egg." She makes a gesture about chicken-egg sized.
Lynn laughs. "That would be very cute. It's entirely possible, too, though if I had to guess I'd say that you'd come from an egg that's bigger than that, if you came from an egg at all."
"Medium-tiny Astrid," says Astrid, making a larger gesture. "I don't remember hatching. But I don't remember anything from before."
"Right, which makes it difficult to figure out where - others that aren't animals but look like humans are. Or what they do."