BehaviorSubject vs Observable?

Question

I\'m looking into Angular RxJs patterns and I don\'t understand the difference between a BehaviorSubject and an Observable.

From my underst

Answer 1

app.component.ts

behaviourService.setName("behaviour");

behaviour.service.ts

private name = new BehaviorSubject("");
getName = this.name.asObservable();`

constructor() {}

setName(data) {
    this.name.next(data);
}

custom.component.ts

behaviourService.subscribe(response=>{
    console.log(response);    //output: behaviour
});