Is it possible to use Python backend and a Android/Native application as Front end
Yes. you can develop a python web service (REST OR SOAP) and use this for the backend for your application. 
also, if you develop a service application (server-client) you must develop a service with python (or any languages) in your server after that connect your mobile application (reactjs, android studio, swift, ...) to this server.
I am handling my second year project which includes some machine learning backend along with a Mobile application front end.In simple terms i am creating
a androing/react native application which would take an input from the user and prosses in a backend development which includes python for some machine learning.
My question is, is it possible  to connect these 2 together. I have gone through some stuff altho i am not very clear on how to create a connection on this. 
Also some opinions on either i should go with android or react native or any other language to go on python or not would be very  useful. 
Thank you