Final answer:
Nonrandom mating occurs when individuals choose their mates based on factors such as physical traits or geographic proximity.
Step-by-step explanation:
Nonrandom mating occurs when individuals choose their mates based on factors such as physical traits or geographic proximity. One reason for nonrandom mating is mate choice, where individuals prefer mates with certain characteristics. Another reason is physical location, where individuals have limited access to potential mates due to geographic barriers.