The baby is 1.5 pounds now and just about 9.5 inches long. He's taking practice breaths of amniotic fluid (or will be soon). His eyelids have been closed for the retinas to develop, but now they're open and he's blinking.
He may be swimming around upside down because apparently its comfortable.
So the additional information from the APA is:
The nerves in the ears are developing and allowing your baby to respond more consistently to the sounds that he hears.