The long, heavy tail of a spider monkey enables the monkey to easily vary its:

• A. body temperature during the day
• B. rate of digestion
• C. ability to vocalize
• D. balance while moving through trees

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by identifying the key anatomical feature mentioned in the problem: the long, heavy tail of the spider monkey. Consider its physical characteristics and potential functions.
2. Step 2: Recall that spider monkeys are arboreal animals, meaning they live in trees. Their tail is prehensile, which means it can grasp and hold objects, acting as an additional limb.
3. Step 3: Evaluate the options provided in the problem. For example, body temperature regulation is typically achieved through physiological processes like sweating or panting, not through the tail. Similarly, digestion and vocalization are unrelated to the tail's structure or function.
4. Step 4: Focus on the spider monkey's movement through trees. The tail provides balance and stability, allowing the monkey to navigate branches and swing efficiently. This is a critical adaptation for arboreal life.
5. Step 5: Conclude that the correct answer is 'balance while moving through trees,' as the tail's primary function is to aid in locomotion and stability in the monkey's tree-dwelling environment.