True or False: The size of the pulp cavity never increases throughout an animal's life.

The statement is true because the size of the pulp cavity does not increase over the course of an animal's life. The pulp cavity contains the dental pulp, which consists of nerves, blood vessels, and connective tissue. As an animal ages, the pulp chamber can actually decrease in size due to secondary dentin formation. This happens as the odontoblasts continue to produce dentin throughout the animal's life, gradually filling the pulp cavity. Thus, the overall size of the pulp cavity generally remains stable or decreases rather than increasing.

The other possibilities, such as variations based on diet or the notion that only older animals may see an increase in pulp cavity size, are not supported by the biological development of teeth. Changes in diet may influence dental health or wear, but they do not affect the fundamental growth patterns of the pulp cavity. Additionally, there is no scientific basis for the idea that the pulp cavity size increases in any context, making the original assertion about its stability throughout an animal's life accurate.