Final answer:
The male dog with a higher testosterone level is usually more likely to succeed in obtaining a female for mating, due to its role in developing male secondary sexual characteristics and reproductive behaviors. Therefore, the correct option is
Step-by-step explanation:
When two male dogs are competing for a female, the dog with a higher level of testosterone will typically have an advantage in obtaining the female. Testosterone is the most potent of the male sex hormones, known as androgens, which also include androsterone.
The functions of testosterone include the development of male secondary sex characteristics, such as increased muscle mass, facial hair, maturation of the sex organs, and sperm production. This hormone is crucial for reproductive behavior and competitiveness in male animals, which can influence their success in mating.