The correct option is Both A and R are true but R is NOT the correct explanation of A
Explanation
The question pertains to the human skeletal system, specifically the appendicular skeleton, which includes the bones of the limbs and their supporting girdles.
Analysis of Assertion (A):
- Correct. The femur, or thigh bone, is the longest, heaviest, and strongest bone in the human body. It extends from the hip to the knee and bears the weight of the body.
Analysis of Reason (R):
- Correct. The pectoral girdle (shoulder girdle) connects the upper limbs to the axial skeleton. Each half of the pectoral girdle consists of two bones: the clavicle (collar bone) and the scapula (shoulder blade).
Analysis of the Relationship:
- The Assertion describes a specific attribute of a lower limb bone (femur), while the Reason describes the anatomical composition of the upper limb girdle (pectoral girdle).
- There is no causal relationship between the composition of the shoulder girdle and the physical properties of the thigh bone. Therefore, R is not the correct explanation for A.
Key Takeaway:
The femur is the longest bone located in the lower limb, whereas the pectoral girdle is located in the shoulder region and comprises the clavicle and scapula.