Selina Textbook Solutions: Movement and Locomotion | Biology Class 9 ICSE PDF Download

 Page 1


Chapter 12. Movement And Locomotion
Exercise 1
Solution A.
1. (b) Cartilage
2. (d) Hip
3. (a) Cervical-7
4. (b) Ear ossicles
Solution B.1.
Parts of the skeleton Location
Transverse process Neural arches in vertebra
Glenoid cavity Pectoral girdle
Shoulder-blade Shoulder girdle
Acetabulum Pelvic girdle
Solution B.2.
1. External Ear
2. Tip of the nose
Solution C.1.
True rib Floating rib
1. The first seven pairs of ribs 
are called true ribs.
1. The last two, i.e., 11
th
 and 
12
th
pairs of ribs are called 
floating ribs.
2. They are attached in front 
of the sternum by means of 
costal cartilages.
2. They are not attached to 
the sternum at all.
Solution C.2.
Muscles pull the structure. A muscle has two ends; a fixed end where the muscle 
originates and a movable end that pulls some other part. The movable end is drawn out 
to form a tough structure known as a tendon that is attached to the bone. When a 
muscle is stimulated by a nerve, it contracts and becomes shorter and thicker and this 
pulls the bone at its movable end. Muscles can only contract and relax, they cannot 
lengthen.
Solution C.3.
Page 2


Chapter 12. Movement And Locomotion
Exercise 1
Solution A.
1. (b) Cartilage
2. (d) Hip
3. (a) Cervical-7
4. (b) Ear ossicles
Solution B.1.
Parts of the skeleton Location
Transverse process Neural arches in vertebra
Glenoid cavity Pectoral girdle
Shoulder-blade Shoulder girdle
Acetabulum Pelvic girdle
Solution B.2.
1. External Ear
2. Tip of the nose
Solution C.1.
True rib Floating rib
1. The first seven pairs of ribs 
are called true ribs.
1. The last two, i.e., 11
th
 and 
12
th
pairs of ribs are called 
floating ribs.
2. They are attached in front 
of the sternum by means of 
costal cartilages.
2. They are not attached to 
the sternum at all.
Solution C.2.
Muscles pull the structure. A muscle has two ends; a fixed end where the muscle 
originates and a movable end that pulls some other part. The movable end is drawn out 
to form a tough structure known as a tendon that is attached to the bone. When a 
muscle is stimulated by a nerve, it contracts and becomes shorter and thicker and this 
pulls the bone at its movable end. Muscles can only contract and relax, they cannot 
lengthen.
Solution C.3.
Bones Corresponding bones
Humerus Thigh bone (Femur)
Tarsals Carpals
Metacarpals Metatarsals
Ulna Fibula
Radius Tibia
Solution C.4.
Once a structure has been moved by a muscle, it cannot return to its original position 
without another muscle acting on it. Muscles that cause opposing movements are known 
as antagonistic muscles.
Example of antagonistic muscles: 
 
When you flex your arm at the elbow, the muscle that lies above the upper arm, i.e. the 
biceps is seen and felt bulging. This muscle bulges due to contraction and becomes 
smaller in length, stiffer and thicker. Contraction of biceps draws the forearm towards the 
upper arm. However, relaxation of biceps cannot push the forearm back to its original 
position. When the arm is extended or straightened, the muscle at the back of the upper 
arm, i.e. the triceps contracts. The two muscles work antagonistically or in opposite 
directions to bend or flex and straighten the arm at the elbow.
Solution C.5.
Some joints like shoulder joint, knee joint need to be held firmly in position to be well-
lubricated. Such joints contain a lubricating fluid called synovial fluid, which serves as a 
cushion between the bones and removes friction during movements. As we age, the joint 
movement becomes stiffer and less flexible because the amount of lubricating fluid inside 
the joints decreases and the cartilage becomes thinner. Ligaments also tend to shorten 
and lose some flexibility, making the joints feel stiff.
Solution D.1.
Uses of skeleton:
Page 3


Chapter 12. Movement And Locomotion
Exercise 1
Solution A.
1. (b) Cartilage
2. (d) Hip
3. (a) Cervical-7
4. (b) Ear ossicles
Solution B.1.
Parts of the skeleton Location
Transverse process Neural arches in vertebra
Glenoid cavity Pectoral girdle
Shoulder-blade Shoulder girdle
Acetabulum Pelvic girdle
Solution B.2.
1. External Ear
2. Tip of the nose
Solution C.1.
True rib Floating rib
1. The first seven pairs of ribs 
are called true ribs.
1. The last two, i.e., 11
th
 and 
12
th
pairs of ribs are called 
floating ribs.
2. They are attached in front 
of the sternum by means of 
costal cartilages.
2. They are not attached to 
the sternum at all.
Solution C.2.
Muscles pull the structure. A muscle has two ends; a fixed end where the muscle 
originates and a movable end that pulls some other part. The movable end is drawn out 
to form a tough structure known as a tendon that is attached to the bone. When a 
muscle is stimulated by a nerve, it contracts and becomes shorter and thicker and this 
pulls the bone at its movable end. Muscles can only contract and relax, they cannot 
lengthen.
Solution C.3.
Bones Corresponding bones
Humerus Thigh bone (Femur)
Tarsals Carpals
Metacarpals Metatarsals
Ulna Fibula
Radius Tibia
Solution C.4.
Once a structure has been moved by a muscle, it cannot return to its original position 
without another muscle acting on it. Muscles that cause opposing movements are known 
as antagonistic muscles.
Example of antagonistic muscles: 
 
When you flex your arm at the elbow, the muscle that lies above the upper arm, i.e. the 
biceps is seen and felt bulging. This muscle bulges due to contraction and becomes 
smaller in length, stiffer and thicker. Contraction of biceps draws the forearm towards the 
upper arm. However, relaxation of biceps cannot push the forearm back to its original 
position. When the arm is extended or straightened, the muscle at the back of the upper 
arm, i.e. the triceps contracts. The two muscles work antagonistically or in opposite 
directions to bend or flex and straighten the arm at the elbow.
Solution C.5.
Some joints like shoulder joint, knee joint need to be held firmly in position to be well-
lubricated. Such joints contain a lubricating fluid called synovial fluid, which serves as a 
cushion between the bones and removes friction during movements. As we age, the joint 
movement becomes stiffer and less flexible because the amount of lubricating fluid inside 
the joints decreases and the cartilage becomes thinner. Ligaments also tend to shorten 
and lose some flexibility, making the joints feel stiff.
Solution D.1.
Uses of skeleton:
1. Support and shape: The skeletal system provides a framework to the body. It 
provides support to all soft parts and gives a definite shape to the body and all 
body parts.
2. Protection: The skeleton protects the internal delicate and important organs of the 
body. For example in human beings, the skull protects thebrain, ribs protect the 
heart and lungs, vertebral column protects the spinal cord, etc.
3. Movement: The skeletal system helps in movement. It co-ordinates the movement 
of attached bones and muscles to bring about locomotion.
4. Leverage: Some bones and joints of the skeletal system form levers and help in 
magnifying, either the movement or the force. For example, slight contraction of 
biceps moves the hand to a distance of about a foot.
5. Formation of blood cells: The skeleton is the site of haematopoiesis. Various 
types of blood cells like red blood cells, white blood cells and platelets are formed in 
the bone marrow of some long bones.
6. Storehouse for minerals: The bones are a storehouse of calcium and phosphorus 
for the rest of the body.
Solution D.2.
Types of joints Example
Immovable joint Skull bones
Partially movable joint Joints between vertebrae
Freely movable joint Hip joint
Gliding joint Ankle bones
Pivot joint
Joint between atlas and axis 
vertebrae
Hinge joint Elbow
Ball and socket joint Shoulder joint
Solution D.3.
Ligament Tendon
Structure
1. Ligament connects two or 
more bones together.
1. Tendon connects muscle to 
a bone.
2. They are elastic. 2. They are inelastic.
3. They are arranged freely.
3. They are arranged in 
bundles.
4. They are formed of yellow 
or elastic fibres.
4. They are formed of white or 
collagen fibres.
Function
1. They help to stabilize joints.
1. They carry tensile forces 
from muscle to bone.
Page 4


Chapter 12. Movement And Locomotion
Exercise 1
Solution A.
1. (b) Cartilage
2. (d) Hip
3. (a) Cervical-7
4. (b) Ear ossicles
Solution B.1.
Parts of the skeleton Location
Transverse process Neural arches in vertebra
Glenoid cavity Pectoral girdle
Shoulder-blade Shoulder girdle
Acetabulum Pelvic girdle
Solution B.2.
1. External Ear
2. Tip of the nose
Solution C.1.
True rib Floating rib
1. The first seven pairs of ribs 
are called true ribs.
1. The last two, i.e., 11
th
 and 
12
th
pairs of ribs are called 
floating ribs.
2. They are attached in front 
of the sternum by means of 
costal cartilages.
2. They are not attached to 
the sternum at all.
Solution C.2.
Muscles pull the structure. A muscle has two ends; a fixed end where the muscle 
originates and a movable end that pulls some other part. The movable end is drawn out 
to form a tough structure known as a tendon that is attached to the bone. When a 
muscle is stimulated by a nerve, it contracts and becomes shorter and thicker and this 
pulls the bone at its movable end. Muscles can only contract and relax, they cannot 
lengthen.
Solution C.3.
Bones Corresponding bones
Humerus Thigh bone (Femur)
Tarsals Carpals
Metacarpals Metatarsals
Ulna Fibula
Radius Tibia
Solution C.4.
Once a structure has been moved by a muscle, it cannot return to its original position 
without another muscle acting on it. Muscles that cause opposing movements are known 
as antagonistic muscles.
Example of antagonistic muscles: 
 
When you flex your arm at the elbow, the muscle that lies above the upper arm, i.e. the 
biceps is seen and felt bulging. This muscle bulges due to contraction and becomes 
smaller in length, stiffer and thicker. Contraction of biceps draws the forearm towards the 
upper arm. However, relaxation of biceps cannot push the forearm back to its original 
position. When the arm is extended or straightened, the muscle at the back of the upper 
arm, i.e. the triceps contracts. The two muscles work antagonistically or in opposite 
directions to bend or flex and straighten the arm at the elbow.
Solution C.5.
Some joints like shoulder joint, knee joint need to be held firmly in position to be well-
lubricated. Such joints contain a lubricating fluid called synovial fluid, which serves as a 
cushion between the bones and removes friction during movements. As we age, the joint 
movement becomes stiffer and less flexible because the amount of lubricating fluid inside 
the joints decreases and the cartilage becomes thinner. Ligaments also tend to shorten 
and lose some flexibility, making the joints feel stiff.
Solution D.1.
Uses of skeleton:
1. Support and shape: The skeletal system provides a framework to the body. It 
provides support to all soft parts and gives a definite shape to the body and all 
body parts.
2. Protection: The skeleton protects the internal delicate and important organs of the 
body. For example in human beings, the skull protects thebrain, ribs protect the 
heart and lungs, vertebral column protects the spinal cord, etc.
3. Movement: The skeletal system helps in movement. It co-ordinates the movement 
of attached bones and muscles to bring about locomotion.
4. Leverage: Some bones and joints of the skeletal system form levers and help in 
magnifying, either the movement or the force. For example, slight contraction of 
biceps moves the hand to a distance of about a foot.
5. Formation of blood cells: The skeleton is the site of haematopoiesis. Various 
types of blood cells like red blood cells, white blood cells and platelets are formed in 
the bone marrow of some long bones.
6. Storehouse for minerals: The bones are a storehouse of calcium and phosphorus 
for the rest of the body.
Solution D.2.
Types of joints Example
Immovable joint Skull bones
Partially movable joint Joints between vertebrae
Freely movable joint Hip joint
Gliding joint Ankle bones
Pivot joint
Joint between atlas and axis 
vertebrae
Hinge joint Elbow
Ball and socket joint Shoulder joint
Solution D.3.
Ligament Tendon
Structure
1. Ligament connects two or 
more bones together.
1. Tendon connects muscle to 
a bone.
2. They are elastic. 2. They are inelastic.
3. They are arranged freely.
3. They are arranged in 
bundles.
4. They are formed of yellow 
or elastic fibres.
4. They are formed of white or 
collagen fibres.
Function
1. They help to stabilize joints.
1. They carry tensile forces 
from muscle to bone.
2. Prevent dislocation 2. Attach muscles to portions 
of the skeleton.
Solution D.4.
(i) Bone is a strong, hollow and non-flexible connective tissue.
(ii) It is hard, greyish-white tissue, composed of 2/3rd of inorganic substances or 
minerals like calcium, phosphorus, carbonates, etc. and 1/3rd of organic substances.
(iii) The outer surface of the bone is called periosteum. Periosteum is a thin, dense 
membrane that consists of outer fibrous and inner cellular layer, nerves and blood vessels 
that nourish the bone.
(iv) The next layer is made up of compact bone. This part is highly calcified, very hard 
and rigid connective tissue. This tissue gives bones a smooth, white and solid 
appearance.
(v) The middle layer of bone consists of bone cells called osteocytes, which are arranged 
in the form of concentric rings. They are embedded in a hard matrix made up of collagen 
fibre and mineral deposits.
(vi) The innermost hollow cavity of long bones contains bone marrow, which produces 
blood cells. Red bone marrow is present at the ends of the bone and produces majority of 
red blood cells, platelets and most of the white blood cells. Yellow bone marrow contains 
higher amount of fat cells than red marrow and helps in the production some white blood 
cells.
(vii) Bones are living tissue as long as they are present in the living body. However, when 
they are taken out of the body, their cells die and the bones are then said to be dead.
Solution D.5.
 
1: Cranium/Skull; 2: Clavicle, Scapula; 3: Sternum; 4: Humerus: 
5: Ulna; 6: Coccyx; 7: Ribs; 8: Radius; 9: Femur; 10: Fibula; 11: Tibia