Are Humans Biologically Programmed To Fear What They Don't Understand?

Makes no sense. Biologically programmed means that response to fear is preordained at conception. Babies in the womb don't fear anything, because they don't understand anything. A young child is ignorant of "fearful" things outside of their immediate surroundings. As one ages, reaction to "fearful" things expands to things usually outside of one's control. Fear is learned, not genetic.

Yes, fear of the other and the unintentional tribal formations that happen are deeply hidden recombinant nucleic acids. PO1 William "Chip" Nagel

Man has always had a fear of the unknown, it's just through curiosity that our fears start to subside.