Which statement best describes the lower body structures of humans and chimpanzees?

• A. Chimpanzees have longer legs relative to their arms compared to humans.
• B. Both humans and chimpanzees have identical lower limb proportions and pelvic shapes.
• C. Humans have a pelvis adapted for upright walking, while chimpanzees have a pelvis suited for quadrupedal movement.
• D. Humans and chimpanzees both possess a valgus knee that aligns the leg directly under the body.

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by analyzing the anatomical differences between humans and chimpanzees, focusing on the pelvis and lower limb structures. Humans are adapted for bipedal locomotion, while chimpanzees are primarily quadrupedal with occasional bipedal movement.
2. Step 2: Understand the role of the pelvis in locomotion. Humans have a bowl-shaped pelvis that supports upright walking and balances the weight of internal organs. Chimpanzees have a narrower pelvis designed for quadrupedal movement, which provides stability when walking on all fours.
3. Step 3: Examine the valgus knee alignment. Both humans and chimpanzees possess a valgus knee, which helps align the leg under the body. However, this feature is more pronounced in humans to support efficient bipedal walking.
4. Step 4: Compare the proportions of the limbs. Humans have longer legs relative to their arms, which aids in bipedal locomotion. Chimpanzees, on the other hand, have longer arms relative to their legs, which is advantageous for climbing and quadrupedal movement.
5. Step 5: Conclude by identifying the correct statement. Based on the anatomical adaptations, the correct answer is: 'Humans have a pelvis adapted for upright walking, while chimpanzees have a pelvis suited for quadrupedal movement.' This reflects the evolutionary differences in locomotion between the two species.