Select the most appropriate one-word substitution for the given group of words.

Dependent on chance or uncertainty

Precarious

The most appropriate one-word substitution for the given group of words "dependent on chance or uncertainty" is precarious.

• Precarious means insecure or dangerous.
• Paradox means a statement that seems contradictory or absurd but may actually be true.
• Presume means to take something for granted or to act without sufficient evidence.
• Presumptuous means arrogant or overconfident.

The word precarious is the most appropriate because it specifically refers to something that is unstable or uncertain. The other words do not have the same connotation of being something that is dependent on chance or luck.