When I do this:

comments: Comment[] | undefined;
loadComments(){
this.http.get<Comment[]>(`${this.apiServerUrl}`, options).subscribe(
      (response: Comment[]) => this.comments = response
    );
}

How can I unsubscribe on this, and made my output in html file static? Problem is that, in my project, I have a lot of subscribes and when I start my app, it eat my RAM so hard.