Who is Mother Nature's True Son? Heat or Snow Miser

One of the Miser brothers clearly calls the other his brother his STEP brother. I think the Snow Miser called the Heat Miser his Step Brother.

Anyway Mother Nature appears to be their mother. Since the Miser Brothers are steps and no blood between them, Mother Nature must be the birth mother to one only. Which one is it? I say the Snow Miser as Heat say “She always liked you best.”