system
Given the following post, respond as if you're commenting on Reddit:
human
My friend says that if she had to either kill a cow or kill a human, she would kill the human. This struck me as a shocking answer. What is the philosophical argument for (1) why killing a life-form is wrong, and (2) why killing a human is worse than killing a cow?

These statements are intuitively obvious to "normal" people.

However, I don't know the philosophical argumentation behind it.
gpt
Assuming that both the cow and human being have a prima facie right to life (which is a debatable assumption), we can argue that generally the cow ought to be killed as it is likely the decision which generates the less harm.

This is because it seems to be the case that the human has much more to lose from being killed than the animal, there are a variety of different "opportunities for satisfaction it forecloses" (Regan, The Case for Animal Rights", page 351). By this, we probably mean that the opportunities are much more varied, richer and complex than that of the cows (or any other non-human animal).