Which of the following choices is a comma splice? a. beetles have mouthparts that are similar to those of grasshoppers. b. these mouthparts are called the mandibles, they are jaw-like structures beetles use for crushing food or defending themselves. c. the antennae of the beetles are used not only to smell but also to feel out their environment. d. the antennae vary greatly among beetles; for some, the antennae are used for self defense.