D. Because when you bite your nails your not in that type of mental state
Answer:
A
Explanation:
because the
Cirulatory system-The skeletal system has many different functions, including supporting the body and giving it shape, protecting internal organs, providing attachment surfaces for skeletal muscles, allowing body movements, producing blood cells, storing minerals, helping to maintain mineral homeostasis, and producing endocrine hormones
The answers is bites from infected insects
