For the life of the flesh is in the blood: and I have given it to you upon the altar to make an atonement for your souls: for it is the blood that maketh an atonement for the soul.(Leviticus 17:11) KJV
We (that’s me and the Holy spirit) deduce that the spirit, a vapor, inhabits the blood through the action of the Hemoglobin molecule and it powers metabolism. The spirit quite literally animates a body and makes it biologically alive.
Hemoglobin is to sentient life what chlorophyll is to plant life. Both molecules have a ring structure which binds Oxygen. In plants chlorophyll produces a supply of Hydrogen to power metabolism. In animals hemoglobin carries Oxygen to the cells.
Those things, which are copies of the heavenly originals, had to be purified in that way. But the heavenly things themselves require much better sacrifices.(Hebrews 9:23) Good News Translation
This pictures for us the very beginning of creation when God used the waters of the deep in nucleosynthesis to create the periodic table of elements and then life. Things on Earth are patterned after things in the heavens, and this extends down to a cellular metabolic level.