Which group includes animals such as arthropods, mollusks, and annelids?

The correct choice is inclusive of invertebrates, which are animals that lack a backbone. This group encompasses a vast variety of organisms, including arthropods (such as insects and crustaceans), mollusks (like snails and octopuses), and annelids (such as earthworms). Invertebrates make up the majority of animal species on Earth and exhibit a wide range of forms, sizes, and ecological roles.

Invertebrates are characterized by their diverse body plans and adaptations that allow them to thrive in various environments, from deep oceans to terrestrial ecosystems. Each subgroup within invertebrates has distinctive features that enable them to survive and reproduce effectively.

In contrast, vertebrates refer specifically to animals that possess a backbone, such as mammals, birds, reptiles, amphibians, and fish. Supplementary consumers and primary producers refer to different ecological roles in food chains, with primary producers being organisms like plants that convert sunlight into energy through photosynthesis, while supplementary consumers are animals that feed on other consumers or primary producers, further complicating the food web. Understanding these classifications helps clarify the vast diversity within the animal kingdom.