Bald is related to Blond in the same way as Barren is related to ?.
Solution
Bald and Blond are related in that they are both terms used to describe characteristics of hair. Bald refers to a lack of hair, while Blond refers to a color of hair.
Similarly, Barren and Fertile are related in that they are opposites concerning the ability to produce offspring or to be productive. Barren refers to the inability to produce, while Fertile refers to the ability to produce, often used in the context of soil, animals, or people (as in fertility).
Thus, the relationship is based on opposites or contrasts between the terms, just as Bald contrasts with Blond, so Barren contrasts with Fertile.