The protagonist is the hero or central character, the focus of the story and it's themes. So unless you define "antagonist" so broadly as to include all possible opposition such as bad luck, geography, and weather, stories are perfectly possible without one.
Consider "To Build a Fire" or "Hatchet" as stories with a protagonist lacking a proper opponent. Conversely, if you consider "antagonist" to indeed include any and all difficulties, then the statement "A Protagonist requires an Antagonist" is a tautology and your answer is no.
To provide obstacles for the protagonist
If antagonist did not want to harm protagonist, he wouldn't be antagonist. His opposition to protagonist is what makes him antagonist.
The antagonist is the opposite to the protagonist.
Brutus is the protagonist, Antony the antagonist.
The protagonist is Flik the antagonist is Hopper
The protagonist is Thor the antagonist is Malekith
the protagonist is Penny the antagonist could be her dad or sister
the protagonist is Stella and the antagonist is joe and paton
tho protagonist is jenna and the antagonist is micheal.
Antinous is an antagonist.
protagonist
A character who is opposed or competes the main character. * is called the antagonist while the main character is called the protagonist,