Android - Prevent Apps from Opening Within Apps

[Khraft]

How do I make apps stop opening within other apps?

 

I just got my very first phone yesterday; it's a Nexus 5 with Android 4.4.2. I'm still learning how to use it...

 

What I mean is that when I open an application, such as Hangouts (SMS Messenger), and then open People (Contacts List), and press the send SMS button on a contact it will open a second Hangouts application that runs inside of People.  Now when I press the recent apps button there will be two Hangouts running, one with the name Hangouts like it should be, and another called People, and when try and open People again it won't bring me to my contacts list, instead it will bring me to the Hangouts running inside of People. (╯°□°)╯︵ ┻━┻

 

I don't want my phone to become a parody of Inception. ಠ_ಠ How do I make it stop doing this?