Law is based on natural law, which is based on morals.

In "Morality as Anti-Nature," Nietzsche critiques traditional morality for going against our natural instincts and desires. He argues that morality restricts our potential for personal growth and authenticity by imposing rigid rules and values that suppress our natural inclinations. Nietzsche advocates for a reevaluation of morality to prioritize individual flourishing and self-expression over conformity to societal norms.

It depends on context. In the legal arena it would be convention. In the religious arena it would most often be natural.

Natural selection has selected the morality we have today, its built In to our instibt to understand eachothers emotions, facial expressions etc, natural selection favours a species with a good morality as this increaaes the survival of offspring, the offspring will normally have the same morality and understanding of emotions and thus pass it on from generation to generation, those that weaker morality would have not been able to reproduce as succesfully as the offspring would have had less help from the others in the community if any, and woud be less likely to make it to adulthood and reproduce,

Additive morality is a theory related to hunting, in opposition to compensatory morality, which states that all the animals killed from hunting would have died anyway from other natural causes and thus hunting doesn't harm the population. Additive morality posits that the animals killed in hunting die in addition to all the natural deaths that occur, and thus hunting decreases the population.