What is a necessary characteristic of hominoids?

Hominoids are a group that includes apes and humans, and one of their defining characteristics is a strong jaw structure, which plays a crucial role in their diet and feeding behaviors. This robust jaw structure allows for the processing of a varied diet, which can include tough plant materials, fruits, and occasionally meat, depending on the specific hominoid species. The strength of their jaws is adapted to their ecological niche and is significant for the mechanics of mastication, which is essential for nutrition and survival.

In contrast, the other options do not reflect necessary characteristics of hominoids. For example, winged anatomy pertains to a completely different group of animals, such as birds and bats, and is not relevant to hominoids. External gestation is not a characteristic of hominoids as they give birth to live young. Flight capability, similar to winged anatomy, applies to birds and other flying animals but not to hominoids, which are primarily terrestrial and adapted to life on the ground and in trees. Thus, the strong jaw structure is indeed a key feature that supports the classification and evolutionary understanding of hominoids.