Final answer:
The phenomenon involving male contests in red deer is mate competition, a type of intrasexual selection where males vie to win the right to mate with females, enhancing their fitness and passing on favorable traits.
Step-by-step explanation:
In the field of Biology, the phenomenon that involves male contests in red deer is b) Mate competition. These interactions are a form of intrasexual selection, where males compete with each other to win the right to mate with females. This type of competition can involve physical confrontations, such as fighting with antlers, or it can include behaviors that showcase strength and health to attract mates.
Similar behaviors can be observed in many other animal species, such as male lions' competition for mating rights, where typically only one male emerges victorious. These behaviors are crucial because they ensure that traits which help animals successfully attract a mate and have offspring, and, therefore, increase their fitness, are passed on to future generations. This natural selection process gradually makes those traits more prevalent in the population.