Final answer:
The question addresses the variability in body composition factors such as weight, sex, age, fatness, and muscling. Weight and sex are less variable, whereas factors like age, fatness, and muscling introduce a broader range of individual differences. Factors such as BMI and slow-twitch to fast-twitch muscle fiber ratio also vary greatly among individuals.
Step-by-step explanation:
The question whether weight and sex are equally described and if age, fatness, and muscling have endless combinations is a complex one. It seems to address the variability in body composition among individuals. While weight and sex are categorical and may seem like simpler descriptors, the other factors like age, fatness, and muscling indeed offer a much broader range of variability. For example, the Body Mass Index (BMI), often used to classify people in terms of weight and fatness, does not differentiate between muscle and fat mass, which can be misleading because two individuals can have the same BMI but different fat and muscle composition.
Moreover, concerning the proportion of slow-twitch to fast-twitch muscle fibers, it's false to say the proportion is the same in all individuals. This varies greatly depending on numerous factors, including genetics and type of physical activity. As for the relationship between height and weight, there is a positive correlation, meaning typically, as height increases, weight does also, albeit with numerous exceptions due to individual body composition differences.