How can animals be separated into groups?

Animals can be separated into groups based on various criteria, including taxonomy (such as kingdom, phylum, class, order, family, genus, and species), habitat (terrestrial, aquatic, or aerial), and dietary habits (herbivores, carnivores, omnivores). Additionally, they can be categorized by their reproductive methods (viviparous, oviparous, or ovoviviparous) or by physiological traits (such as warm-blooded versus cold-blooded). These classifications help scientists and researchers understand animal behavior, ecology, and evolution.