When applying for registration, what must a rabbit meet according to senior breed requirements?

In the context of registering a rabbit, the correct answer focuses on the necessity for the rabbit to fulfill all senior breed requirements. This is crucial because senior breed requirements encompass all aspects needed to ensure that the rabbit meets the standards set by the breed's governing body, which often includes specific characteristics, qualities, and descriptions relevant to adult rabbits.

Senior breed requirements are designed to maintain the integrity of the breed and may include factors such as age, physical characteristics, and specific breed standards. By meeting all these requirements, the rabbit demonstrates that it adheres to the intended traits of the breed, which is essential for successful registration.

The other options, while related to the topic, do not capture the comprehensive nature of the criteria that must be met for senior registration. For instance, only fulfilling junior breed requirements would not suffice, as senior standards are more stringent and detailed. Similarly, stating "no specific requirements" overlooks the essential criteria needed for proper breed establishment and maintenance. Lastly, focusing solely on weight requirements is too narrow and disregards many other important standards that reflect the rabbit’s overall quality and breed characteristics.