medical field will allow me to care for them as they transition into older age
"take care of them" , perhaps?
I know that there will be many times when they will need to go to the hospital to get check-ups and eventually they will get sick
this sentence is kind of a turn-off to the atmosphere you created, try soething catchy
I feel drawn to biology and the medical field because of the many difficulties that my family has faced
you need a stronger introductory sentence. this is just the "i like biology because this and this ad this" although your reasons are quite strong.
I think its a good essay, and you dont have much words to write either, but maybe u could involve one more aspect to why you would liek to study biology. I mean, its brown so this essay can make a difference.
so try considering rewriting these sentences:
I know that there will be many times when they will need to go to the hospital to get check-ups and eventually they will get sick. I hope that with a background in human biology, I will be able to understand medical jargon and give them some advice when considering treatment options. Therefore, I hope to have a future in the medical field at Brown University. (941/1000)
but still, just a suggestion ;)
good luck! i hope you get in!