render() {
    return (
      <div>
        <Navbar 
          score={this.state.score}
        />
        <Jumbotron />
        <div className="wrapper">
          {this.state.hero.map(hero => (
            <Card
              imageClick={this.imageClick}
              id={hero.id}
              key={hero.id}
              image={hero.image}
            />
          ))}
        </div>
        <Footer />
      </div>
    );
  }
//the order of components to be rendered: navbar, jumbotron, Card, footer 
the order of components to be rendered: navbar, jumbotron, Card, footer
the order of components to be rendered : navbar jumbotron Card footer
render() {
    return (
      <div>
        <Navbar 
          score={this.state.score}
        />
        <Jumbotron />
        <div className="wrapper">
          {this.state.hero.map(hero => (
            <Card
              imageClick={this.imageClick}
              id={hero.id}
              key={hero.id}
              image={hero.image}
            />
          ))}
        </div>
        <Footer />
      </div>
    );
  }
render ( ) { return ( < div > < Navbar score = { this . state . score } / > < Jumbotron / > < div className = "wrapper" > { this . state . hero . map ( hero => ( < Card imageClick = { this . imageClick } id = { hero . id } key = { hero . id } image = { hero . image } / > ) ) } < / div > < Footer / > < / div > ) ; }
the order of components to be rendered: navbar, jumbotron, Card, footer
the order of components to be rendered : navbar jumbotron Card footer