human beings. That has been settled science for a century:
https://prolifepages.wordpress.com/2012/09/19/when-does-human-life-begin/
The cessation of brain waves in a living human is the current scientific standard for when a human being has died.
Just because we cannot yet detect the brain waves of an unborn human being until about 40 days after he or she has been conceived does NOT mean that that human being is somehow something other than a human being.
https://christiananswers.net/q-sum/q-life019.html