NCERT-Based Explanation
NCERT states that the pectoral and pelvic girdles help in the articulation of the upper and lower limbs with the axial skeleton. Therefore, the assertion is true.
The term “girdle” is an anatomical name describing a belt-like or encircling bony structure that attaches the limbs to the axial skeleton. It is not named “girdle” because it helps in articulation. Hence, the reason is false.

Pedagogical Value
This question distinguishes between the function of a structure and the origin of its anatomical name. Students often assume that anatomical terms are named after their functions. The question encourages them to recognise that many anatomical names are based on shape, appearance, or position, rather than physiological role.

NCERT-Based Explanation
NCERT states that the trachea divides into the right and left primary bronchi at the level of the 5th thoracic vertebra. The reason is incorrect because it states only “5th vertebra”, not mentioned the type of vertebra. This is anatomically ambiguous and scientifically inaccurate. The scapula extends approximately from the 2nd to the 7th ribs (or corresponding thoracic vertebral levels), making the assertion true.

Pedagogical Value
This question encourages students to compare the approximate anatomical extent of the trachea and the scapula by visualising their positions rather than relying solely on memorised facts.

NCERT-Based Explanation
The Assertion is true. Direct NCERT: Each rib has two articulation surfaces and is therefore called bicephalic.
The Reason is false. Direct NCERT: The two articulation surfaces are present on the dorsal end of each rib, not on the ventral side.

Pedagogical Value
This question develops anatomical visualisation skills. Students should mentally picture the orientation of a rib in the body and identify that its two articulation surfaces are located at the dorsal end, where it articulates with the vertebral column, not at the ventral end. It encourages students to verify positional information through mental visualisation rather than relying solely on memorised facts, enabling them to detect such errors immediately.

NCERT-Based Explanation
The Assertion is false. Direct NCERT: In human beings, the skeletal system is made up of 206 bones and a few cartilages, not simply “206 bones and cartilages.”
The Reason is true. Direct NCERT: The axial skeleton comprises 80 bones, while the appendicular skeleton comprises 126 bones.

Pedagogical Value
This question addresses the common misconception that the human skeletal system consists only of 206 bones. It reminds students that, according to NCERT, the skeletal system includes 206 bones and a few cartilages, while also reinforcing the division of the 206 bones into the axial (80) and appendicular (126) skeletons.

NCERT-Based Explanation
The Assertion is false. The spinal cord does not protect the nerve cord. In human beings, the spinal cord itself is the nerve cord. Direct NCERT: The vertebral column protects the spinal cord.
The Reason is also false. The pronoun “It” refers to the spinal cord (the subject of the Assertion). The spinal cord does not support the head or serve as the point of attachment for the ribs and musculature of the back. These are functions of the vertebral column, as stated in NCERT.

Pedagogical Value
This question addresses the common misconception that the spinal cord and the vertebral column are the same structures. It encourages students to distinguish between the spinal cord (neural tissue) and the vertebral column (skeletal structure), particularly with respect to protection, support, and sites of muscle and rib attachment.

NCERT-Based Explanation
The glenoid cavity is a shallow socket of the scapula situated below the acromion. The head of the humerus articulates with the glenoid cavity to form the shoulder joint. Therefore, both the assertion and the reason are true, but the reason does not explains the assertion.

Pedagogical Value
This question tests the student’s ability to visualise the anatomy of the scapula and identify the relative positions of the acromion and the glenoid cavity, along with the articulation forming the shoulder joint.

NCERT-Based Explanation
The Assertion is false. Direct NCERT: The scapula is a flat bone of the appendicular skeleton, but flat bones are not restricted to the appendicular skeleton. The sternum (axial skeleton) is also a flat bone. kebo120.pdfPDF kebo120.pdfPDF
The Reason is true. Direct NCERT: The scapula is a large triangular flat bone situated in the dorsal part of the thorax. kebo120.pdfPDF
The Reason does not explain the false Assertion.

Pedagogical Value
This question addresses the common misconception that the occurrence of a particular bone type is restricted to one division of the skeleton. It encourages students to mentally visualise both the axial and appendicular skeleton and identify examples of flat bones in each, rather than associating a bone type exclusively with one skeletal division.

Revised NCERT-Based Explanation
The Assertion and Reason are false. Direct NCERT: Each vertebra has a “central hollow portion” called the neural canal through which the spinal cord passes. The term “dorsal hollow portion” is incorrect.

Pedagogical Value
This question addresses the common misconception that the neural canal is dorsally located within a vertebra. It reinforces the precise NCERT description that the neural canal is the central hollow portion of each vertebra through which the spinal cord passes, helping students avoid confusing the anatomical position of the vertebra with the location of the neural canal within it.

NCERT-Based Explanation

The Assertion is true as a logical inference. Direct NCERT: Red muscle fibres contain a large amount of myoglobin, which stores oxygen, and possess numerous mitochondria, enabling them to sustain activity for longer periods. Thus, muscles with greater oxygen demand generally contain more myoglobin and appear redder.

The Reason is also true as a logical inference. Myoglobin is an oxygen-binding protein and is responsible for the red colour of muscle fibres. Although NCERT states that myoglobin stores oxygen and that red fibres contain more myoglobin, it does not directly state that myoglobin is a red protein. This is standard biological knowledge beyond the explicit NCERT text.

Therefore, the Reason explains the Assertion.

Pedagogical Value

This question encourages students to connect structure, colour, and function instead of studying them as independent facts. It promotes the understanding that the redness of muscle is not merely a visual characteristic but reflects the abundance of myoglobin, which in turn is associated with the muscle’s oxygen requirement and aerobic activity. It also encourages students to infer biological relationships from NCERT concepts rather than relying solely on memorisation.

NCERT-Based Explanation
NCERT states that the pelvic girdle consists of two coxal bones, and each coxal bone is formed by the fusion of ilium, ischium and pubis. Hence, the reason is false because “ileum” is a part of the digestive system, whereas “ilium” is one of the three bones forming the coxal bone.
Although NCERT does not explicitly classify the coxal bone as a flat bone, anatomically it is regarded as a flattened bone despite its projections and irregular contours. Similarly, NCERT describes the scapula as a flat bone even though it possesses a prominent spine. Therefore, the presence of projections does not preclude a bone from being classified as a flat bone. Hence, the assertion is true, whereas the reason is false.

Pedagogical Value
This question has two independent learning objectives.

Students often interpret the term “flat bone” too literally.
This question encourages them to understand that anatomical classification is based on the overall morphology of a bone, not on the absence of projections or ridges.
Just as the scapula is classified as a flat bone despite having a prominent spine, the coxal bone should not be judged merely because the pubic region projects anteriorly.

The deliberate use of “ileum” instead of “ilium” reminds students that a single letter can completely change the meaning of a biological term.
It reinforces the importance of reading every scientific term carefully rather than relying on intuition or pattern recognition.

NCERT-Based Explanation
The Assertion is false. Direct NCERT: Bone has a very hard matrix due to calcium salts, whereas cartilage has a slightly pliable matrix due to chondroitin salts. The Assertion incorrectly reverses these properties.
The Reason is true. Direct NCERT: Bone has a very hard matrix because it contains calcium salts.

Pedagogical Value
This question addresses the common misconception that bone and cartilage differ only in the amount of calcium salts, leading students to confuse their matrix properties. It reinforces the distinction that bone has a hard, calcium salt-rich matrix, whereas cartilage has a slightly pliable matrix due to chondroitin salts, preventing reversal of these fundamental NCERT characteristics.

NCERT-Based Explanation
The Assertion is false as a logical inference. NCERT states that white muscle fibres depend on anaerobic processes for energy. Therefore, cutting off the oxygen supply does not cause them to stop contracting immediately, as their ATP production is not primarily dependent on oxygen.
The Reason is true. Direct NCERT: White muscle fibres possess fewer mitochondria and depend on anaerobic processes for energy.

Pedagogical Value
This question addresses the common misconception that interrupting oxygen supply immediately stops muscle contraction, irrespective of muscle fibre type. It encourages students to relate the predominantly anaerobic metabolism of white muscle fibres to their ability to continue ATP production in the absence of oxygen, while distinguishing metabolic preference from immediate physiological response.

NCERT-Based Explanation
Most ribs articulate posteriorly with the vertebral column. However, only the first seven pairs articulate directly with the sternum, the 8th–10th pairs articulate indirectly through costal cartilage, and the 11th and 12th pairs (floating ribs) do not articulate with the sternum. Therefore, not every rib articulates with a ventral bone.
The term bicephalic refers to the head of a typical rib having two articular facets, which articulate with the bodies of two adjacent thoracic vertebrae. It does not mean that a rib articulates with two bones located on the dorsal and ventral sides.

Pedagogical Value
This question tests whether students distinguish between the articulations of a rib and the anatomical meaning of the term “bicephalic.” It prevents students from inferring the meaning of technical terms from superficial observations and reinforces the structural features of a typical rib.

NCERT-Based Explanation
NCERT states that the two halves of the pelvic girdle meet ventrally to form the pubic symphysis, which contains fibrocartilage. Therefore, the assertion is false because it incorrectly states dorsally instead of ventrally, whereas the reason is true.
Pedagogical Value
This question tests whether students can correctly visualise the orientation of the pelvic girdle and the location of the pubic symphysis. It also reinforces the structural composition of the pubic symphysis and discourages answering based on intuition.

NCERT-Based Explanation
The Assertion is false. Direct NCERT: Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes. Therefore, stating that the spinal cord passes through the dorsal hollow portion of the vertebra is incorrect.
The Reason is true as a biological fact. In human beings (chordates), the nerve cord is dorsal. However, this is not stated in the NCERT chapter on Locomotion and Movement. It also does not explain why the spinal cord passes through the central neural canal rather than a dorsal hollow portion.

Pedagogical Value
This question addresses the common misconception that because the nerve cord is dorsally located in chordates, the neural canal within each vertebra must also be dorsal. It encourages students to distinguish between the position of the spinal cord within the body and the position of the neural canal within an individual vertebra, thereby preventing incorrect transfer of anatomical terminology.

NCERT-Based Explanation
NCERT states that joints help in movement and are essential for locomotion. However, not all types of movements require joints. For example, movements such as cyclosis (cytoplasmic streaming), ciliary movement, flagellar movement, and amoeboid movement occur without the involvement of joints. Therefore, the assertion is false. The reason is true because locomotion, such as walking, running and jumping, depends on the coordinated action of joints, including the hip, knee, ankle and shoulder joints.

Pedagogical Value
This question distinguishes between the broader concept of movement and the specific type of movement called locomotion. It discourages students from assuming that all movements in living organisms involve joints and reinforces the NCERT classification of different types of movements.

NCERT-Based Explanation
The Assertion is false. Direct NCERT: White muscle fibres possess a well-developed sarcoplasmic reticulum, whereas red muscle fibres are characterised by abundant myoglobin and numerous mitochondria. Therefore, the redness of a muscle is not directly proportional to the size or volume of its sarcoplasmic reticulum.
The Reason is also false. Although red muscle fibres are aerobic, it is incorrect to state that more calcium ions are needed for their contraction and relaxation. NCERT does not relate the aerobic nature of red muscle fibres to a greater calcium requirement. Muscle contraction and relaxation depend on the regulated release and reuptake of calcium ions, not on red muscle fibres requiring a greater quantity of calcium.

Pedagogical Value
This question addresses the common misconception that red muscle fibres require more calcium ions simply because they contain more myoglobin and predominantly undergo aerobic metabolism. Students often incorrectly associate higher aerobic capacity with a greater calcium requirement for contraction and relaxation. The question encourages them to distinguish metabolic adaptations (high myoglobin and abundant mitochondria) from the calcium-handling mechanism involved in muscle contraction and relaxation, thereby preventing overgeneralisation of the characteristics of red muscle fibres.

NCERT-Based Explanation
The Assertion and reason are true as a logical inference. Direct NCERT: The scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and seventh ribs. Since the vertebral column lies in the midline and the scapula is present on either side of it, the scapula is lateral to the vertebrae. Reason doesnot explain the assertion.

Pedagogical Value
This question develops anatomical visualisation. Students should mentally locate the scapula with respect to the vertebral column and the thorax. From the NCERT description that the scapula lies in the dorsal part of the thorax, they should infer that it is positioned lateral to the vertebral column, rather than merely memorising anatomical terms.

NCERT-Based Explanation
The Assertion is false as a logical inference. Although red muscle fibres are predominantly aerobic, they do not stop contracting immediately when the oxygen supply is cut off. NCERT states that repeated activation of muscles leads to lactic acid accumulation due to anaerobic breakdown of glycogen, indicating that muscles are capable of anaerobic ATP production. Therefore, interruption of oxygen supply does not imply an immediate cessation of contraction.
The Reason is true. Direct NCERT: Red muscle fibres contain abundant myoglobin and numerous mitochondria, utilise stored oxygen for ATP production, and are therefore called aerobic muscles.

Pedagogical Value
This question addresses the common misconception that aerobic muscles can function only in the presence of oxygen. Students often assume that cutting off oxygen results in the immediate cessation of contraction. The question encourages them to integrate NCERT statements on aerobic metabolism and anaerobic breakdown of glycogen, leading to the understanding that muscles can temporarily switch to anaerobic ATP production rather than stop contracting immediately. This develops the habit of connecting related NCERT concepts instead of interpreting individual statements in isolation.

NCERT-Based Explanation
The clavicle has a double curvature, but the two curvatures are not in the same orientation. The medial two-thirds is convex anteriorly, whereas the lateral one-third is concave anteriorly. Hence, the assertion is false. The double curvature of the clavicle is not meant to make the thoracic cage airtight; therefore, the reason is also false.
Pedagogical Value
This question tests the student’s understanding of the shape of the clavicle and prevents them from making incorrect functional associations with the thoracic cage.