Final answer:
The ilium of a chimpanzee is narrow and tall and lies in the frontal (coronal) plane, which divides the body into front and back portions.
Step-by-step explanation:
The ilium of a chimpanzee is narrow and tall, lying in the frontal (coronal) plane, which is a plane that cuts through an animal, separating it into front and back portions. This is different from the fusiform body shape, which is tubular and tapered at both ends. In primates like chimpanzees, the structure of the pelvis and its alignment in the frontal plane are significant for locomotion and posture.