Answer:
Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
Step-by-step explanation:
Testosterone is an anabolic steroid that acts as the primary male sex hormone.
Testosterone is an androstanoid and it has 17beta-hydroxy and 3-oxo groups along with unsaturation at C-4-C-5.
On the other hand, estradiol is the major female sex hormone which is also a steroid hormone.
The structure of estradiol is such that it has 17 beta-hydroxy groups attached to it.
The difference in the structure of the two hormones is shown in the attached figure.