“And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.”
Man was the only thing in the Bible that was created from substances that were already created by God. Everything else, God spoke into existence. And, then, God breathed the "breath of life" into him.
So, what is the breath of life? According to Got Questions It is the life and power of God, given to man to animate him. The Hebrew word for spirit is ruach, which means “wind, breath, air, spirit.” In short, man is the only living being on the face of the earth that has the Spirit of God in him. Animals, which do possess souls, do not possess the Spirit. (Read Bible Sprout's "Do Animals Have Eternal Souls" for further information on this topic)