Genesis 3:9 (ESV)

9 But the LORD God called to the man and said to him, “Where are you?”

Now the Lord comes with his questions. He does not do this because he does not know the answers. He asks Adam and Eve these things to make them discover what they have done. The answers to these questions also reveal how deeply sin has entered into man.

It is striking that God addresses his first question, Where are you? to Adam only. Here we see that Adam is the head, the first responsible to God.