What kind of apps can I build

Getting Started Newbie Questions
#1

I was working on my second game and I wanted to know if I could build more than just games . E.g social media apps, app security apps, etc .

#2

Yes.

#3

Yes

https://play.google.com/store/apps/details?id=me.menu.eater&hl=en

(An app I wrote for a client.)

#4

Yes.

#5

Yes

https://play.google.com/store/apps/details?id=me.menu.eater&hl=en

(An app I wrote for a client.)