Составить вопросы к этому предложению "the heart is composed of cardiac muscles"

The heart is composed of cardiac muscles, isn't it? (разделит.)

Is the heart composed of cardiac muscles? (общий)

What is composed of cardiac muscles? (к подлежащему)

What is the heart composed of? (спец.)

Is the heart or liver composed of cardiac muscles? (альтернативный)