STD-5, CHAPTER-1: MY BODY, EXTRA QUESTION ANSWERS

 1.      How does our body work?

Ans: Our body works with the help of various organs present in it.

2.      What are organs?

Ans: Organs are special structures present in our body that perform specific functions.

3.      What is an organ system?

Ans: An organ system is a group of organs that work together for a particular function.

4.      Name the organs present in the digestive system.

Ans: The mouth, food pipe, stomach, and intestines are present in the digestive system.

5.      What is breathing?

Ans: The process of taking in oxygen and giving out carbon dioxide is called breathing.

6.      Name the organs present in human breathing system.

Ans: Nose, wind pipe and lungs are the parts of the human breathing system.

7.      How the process of breathing takes place?

Ans: i) We inhale air through the nasal openings of the nose.

ii) From the nose, air goes to the lungs through the wind pipe.

iii) In the lungs, oxygen is taken up by the blood and carbon dioxide is unloaded.

iv) This carbon dioxide is then exhaled through the nose.

8.      How the blood helps in breathing?

Ans: i) Blood circulates the oxygen from lungs to all parts of our body.

ii) Blood also collects carbon dioxide from all parts of the body and brings it to the lungs.

9.      _______ gas is consumed in the process of breathing.

Ans: Oxygen

10.  ________ gas is driven out of the body as a waste product, in the process of breathing.

Ans: Carbon dioxide

11.  How physical exercises help us?

Ans: Physical exercises, like running, walking and playing, help to keep our body and breathing system healthy.

12.  State the importance of Skeletal system of our body.

Ans: i) Skeletal system makes the framework of our body.

ii) It gives shape and support to the body.

iii) The skeletal framework also protects the inner delicate organs.

13.  The human being is made up of ______ bones of different sizes and shapes.

Ans: 206 bones

14.  A child is having ______ bones, when born.

Ans: More than 300 bones

15.  Why the number of bones decrease as the baby grows into an adult?

Ans: As the child grows, some bones get fused together. So, the number of bones decreases in the adult stage.

16.  Write four lines about bones.

Ans: i) Bones are hard and strong structures.

ii) They are made up of calcium, phosphorus and some other minerals.

iii) Bones are living entities.

iv) They have channels that contain blood vessels.

17.  Why can we feel pain when any of our bones gets hurt?

Ans: i) Bones are living entities. They have channels that contain blood vessels.

ii) They also have nerves that are necessary to keep them alive.

That is why we feel pain when any of our bones gets hurt.

18.  What is bone marrow?

Ans: Cells and soft materials in the hollow space of long bones, is called as the bone marrow.

19.  Name the bones which are hollow from inside.

Ans: Thigh bones and arm bones are hollow from inside.

20.  The ______ is known as the factory for making blood cells.

Ans: Bone marrow

21.  Why is the bone marrow known as the factory for making blood cells?

Ans: Blood cells are manufactured inside the bone marrow. So, the bone marrow is known as the factory for making blood cells.

22.  Name the main parts of the skeletal system.

Ans: The main parts of the skeletal system are, i) The skull,      ii) the backbone,     iii) The Rib-cage and iv) The limbs.

23.  Name the part which protects our brain.

Ans: The skull protects our brain.

24.  The skull is made up of ______ flat bones.

Ans: Eight

25.  What is the importance of skull in humans?

Ans: Skull is important as it protects our brain.

26.  Name the most important part of human body.

Ans: The Brain

27.  Name the two jaws. Which one is movable?

Ans: The two jaws are- upper jaw and lower jaw. The lower jaw is movable.

28.  How the movement of lower jaw is helpful?

Ans: The movement of lower jaw helps us to eat, talk or laugh.

29.  How many small bones are present in our backbone?

Ans: Thirty three small bones are present in our backbone.

30.  What are vertebraes?

Ans: The small bones present in the vertebral column (backbone), are called as vertebraes.

31.  How the vertebral column (backbone is formed)?

Ans: Thirty-three small bones called vertebraes, when taken together forms the strong vertebral column (backbone).

32.  Which organ is protected inside the vertebral column?

Ans: Spinal cord is protected inside the vertebral column.

33.  Why is our backbone made up of many small vertebrae instead of one straight long bone?

(OR) What would happen if our backbone was made of just one straight bone?

Ans: i) The small bones give flexibility to our back.

ii) If the backbone was made up of only one bone, then our back would have become rigid and we would not be able to move.

34.  How many bones are present in the human neck?

Ans: There are seven bones in the human neck.

35.  Name another living organism whose neck also contains seven bones.

Ans: Giraffe’s neck also contains seven bones.

36.  State the importance of rib-cage in our body.

Ans: The rib-cage protects delicate organs like the heart and the lungs.

37.  How the rib-cage is formed?

Ans: i) Twelve pairs of ribs join together to form a cage like structure called the rib cage.

ii)  The ribs are curved bones joined to the backbone and the breast bone.

38.  What are floating bones? Why are they named so?

Ans: The last two pairs of ribs are called floating bones.  This is because, they are connected to the backbone only and not to the breast bone.

39.  The floating bones are joined to the ______ only.

Ans: Backbone

40.  What is the other name of the arms?

Ans: Fore limbs

41.  How are fore limbs connected to the spine?

Ans: The fore limbs, or the arms are joined to the spine by the shoulder girdles and collar bone.

42.  How many bones are present in the upper arm, and lower arm?

Ans: i) The upper arm has only one bone.

ii) The lower arm has two bones.

43.  What is the other name of the legs?

Ans:  Hind limbs

44.  What is the function of Hind limbs (legs)?

Ans: The hind limbs (legs) bear the weight of the whole body. It also helps in moving from one place to another.

45.  Name the longest bone in our body. Where is it present?

Ans: Femur (thigh bone), is the longest bone in our body. It is present in the upper part of the hind limbs.

46.  How the Femur (thigh bone) is connected to other bones?

Ans:i) The femur, fits into the hip girdle.

ii) The femur is also connected to the lower two bones of the leg at the knee.

47.  Name the smallest bone in our body. Where is it present?

Ans: Stirrup (stapes) is the smallest bone. It is present in the ear.

48.  What are joints?

Ans: The places where the bones are held together are called as joints.

49.  What is a cartilage?

Ans: A cartilage is a tough, smooth elastic structure that cushions bones at their joints.

50.  What is the importance of cartilage and slippery fluid at the joints?

(OR) Why do bones have joints?

 Ans: i) Our bones have joints, to hold the bones together. It also allows different types of movement.

ii) Coating of cartilage and the slippery fluid are important so that the bones do not scratch and bump against each other when we move.

51.  What are ligaments? State its function.

Ans: Ligament is a strong stretchy band like tissue which attaches bones together at joints.

52.  Why the joints of bones in the skull do not show movement?

Ans: The bones of the skull are fused and interlocked and thus, show no movement.

53.  We have over 230 movable and _________ joints in our body.

Ans: Semi-movable

54.  Name the four types of joints.

Ans: The four types of joints are, hinge joint, ball and socket joint, pivot joint and gliding joint.

55.  Name the body parts where hinge joint is present.

And: The elbow, knee, toe and finger joints are hinge joints.

56.  How does a hinge joint work?

Ans: i) A hinge joint works like a door.

ii) The bones, connected by this joint, move in one plane only.

iii) This joint provides back and forth movement of the body part.

57.  What is Arthritis?

Ans: Arthritis is a disease that causes joint pain, swelling and stiffness.

58.  How does a ball and socket joint work?

Ans: i) In ball and socket joints, a bone which has a ball-like end, fits into the hollow socket of another bone.

ii) This type of joint allows free movement of the bones, both in forward and backward directions.

iii) The hip and shoulder joints are examples of this type of joint.

59.  Name the parts of body which are joined by pivot joint.

Ans: Pivot joint is found between the skull and the first two vertebrae of the spine.

60.  How the movement of our skull indicates yes or no, to a thing?

Ans: i) When the head moves up and down, it signals yes.

ii) When it moves sideways, it signals no.

61.  How Pivot joints are formed?

Ans: In pivot joints, one bone fits into a ring formed by the other bone.

62.  Name the parts of the body having Gliding joint.

Ans: Gliding joint is present in wrist, ankle and between any two vertebrae of the spine.

63.  How gliding joints are helpful?

Ans: i) Gliding joints provide flexibility to our backbone.

ii) We are able to bend forward or backward, or sideways, owing to the presence of the gliding joint in the vertebrae.

64.  Name the sense organs of human body.

Ans: Nose, ears, eyes, tongue and skin are the sense organs.

65.  How the Sense organs help us?

Ans: Our sense organs collect information and send it to the brain for processing.

66.  Each eyeball is placed in a _______ in the skull.

Ans: Bony socket

67.  What is the function of eyelids and eyelashes?

Ans: Eyelids and eyelashes protect our eyes from dust and dirt.

68.  What is iris?

Ans: The dark structure, in front of the eyeball, is called the iris.

69.  What is pupil?

Ans: The small round black spot, in the centre of iris, is called the pupil.

70.  What is the function of Pupil?

Ans: The pupil allows light to enter the eye.

71.  Light enters into the eyes through the ______.

Ans: Pupil

72.  What is retina?

Ans: A retina is a screen, at the back of the eyeball, where all images get formed.

73.  The eye is connected to the brain by a nerve called ______.

Ans: The optic nerve

74.  ‘A chameleon can see in two different directions at the same time.’- Justify.

Ans: The two eyes of a chameleon can move independently. Therefore, it can see in two different directions at the same time.

75.  How nose enables us to smell different substances?

Ans: There are nerve endings present in the nose which carry message about any chemical substance (odour/fragrance) that enters the nose. This enables us to smell different substances.

76.  Name the parts of the human ear.

Ans: The parts of the human ear are- the outer ear, middle ear and the inner ear.

77.  What is external ear?

Ans: The portion of the ear, which is visible to us, is known as the external ear.

78.  Write the functions of different parts of the ear.

Ans: i) The outer ear directs the sound to the inner ear.

ii) The middle ear has an ear drum, and three small bones which convey the vibrations from the ear drum to the inner ear.

iii) The inner ear helps us to hear and maintain the balance of our body.

79.  State the role of inner ear in the process of hearing.

Ans: i) The inner ear collects the sound waves from the middle ear and passes them to the brain.

ii) Thus, it helps us to hear and maintain the balance of our body.

80.  What is the function of taste buds in the tongue?

Ans: Taste buds, in the tongue are sensitive to different tastes, like sweet, sour, bitter and salty.

81.  What is the number of taste buds in human tongue?

Ans: Human tongue has about 9,000 taste buds.

82.  Name the largest sense organ of our body.

Ans: Skin is the largest sense organ of our body.

83.  How the skin helps us?

Ans: i) The skin forms a natural protective covering of the entire body.

ii) It helps us to feel pain, touch, pressure, hotness and coldness.

84.  There are ______ in the skin which help us to feel the sensations.

Ans: Sensory structures.

85.  How do the insects respond to the sensations of smell and taste?

Ans: i) Insects, such as cockroach, housefly and butterfly have feelers on their bodies.

ii) These insects smell and taste with the help of these feelers.

iii) The housefly tastes with its legs.

iv) Insects, like house cricket, can hear through their legs.

86.  How do water animals (fishes) detect the presence of an enemy or a prey?

Ans: i) The water animals have lateral lines.

ii) They can feel the waves produced in water by other living animals, through these lateral lines.

iii) This helps them to detect their prey or to know about the enemy present around them.

87.  Why do birds make sounds?

Ans: i) Birds make different sounds to inform other birds about different situations.

ii) They make sound, when there is an enemy around.

iii) They make sound when they see the availability of food.

iv) Birds also group together and make sounds for setting out in search of food or to call all members for taking rest after day’s work.

88.  Name one reptile.

Ans: Snake is a reptile.

89.  How does a snake detect the presence of an enemy or a prey?

Ans: The snake feels different kinds of vibrations on the earth through its skin. This helps it to detect the presence of an enemy, a danger or a prey.

90.  How the tongue of a snake is helpful to it?

Ans:i) The long tongue helps the snake to feel and smell.

ii) The snake senses the availability of food through its tongue only.

91.  Name some mammals.

Ans: Human being, Dog and Bats, are mammals.

92.  Dogs and bats are also mammals like us. How does our sense of smell compare with that of a dog and our sense of hearing with that of a bat?

Ans:i) Dogs have highly developed sense of smell as compared to human beings.

ii) Bats can hear high-pitched sounds whereas human ears cannot hear those sounds.

93.  Define ultrasonic sounds.

Ans: Ultrasonic sounds are high-pitched sounds that humans cannot hear.

94.  ‘Bats hunt at night.’- comment on this statement.

Ans: i) Bats have a special power to hear high-pitched sounds.

ii) Due to this ability, bats can detect their prey easily even in the dark, with the help of high-pitched sound.

This is the reason why bats hunt at night.

STD-5, CHAPTER-12, OBSERVING THE SKY, EXTRA QUESTION ANSWERS

1.      The sun rises in the _____.

Ans: East

2.      The sun sets in the _____.

Ans: West

3.      State the cause of the apparent motion of the sun from east to west?

Ans: As the earth rotates from west to east, the sun appears to move from east to west.

4.      Name the morning star.

Ans: Mercury or venus

5.      Name the evening star.

Ans: Mercury or venus

6.      In which part of the sky are we likely to find Venus when it is visible as an evening star?

Ans: Venus is seen very low near the horizon in the sky.

7.      Name the brightest and most recognisable object in the night sky.

Ans: The moon is the brightest and most recognisable object in the night sky.

8.      Name the brightest object in the sky after the sun and the moon.

Ans: Venus is the brightest object in the sky after the sun and the moon.

9.      Name the planets which can be seen in the night sky even with the unaided eye.

Ans: Mars, venus, Jupiter and Saturn are the planets that can be seen in the night sky even with the unaided eye.

10.  Why cannot we see Uranus and Neptune with unaided eye?

Ans: We cannot see Uranus and Neptune with unaided eye, because they are very faint.

11.  Name the first planet discovered by using a telescope.

Ans: Saturn was the first planet discovered by using a telescope.

12.  How can we know about the temperature of stars from their colours?

Ans: The hottest stars shine with a whitish-blue light.

The other stars shine with a yellowish white light.

13.  The sun shines with a ______ light.

Ans: Yellowish-white light.

14.  Name the star nearest to the Earth.

Ans: The nearest star to the Earth is the Sun.

15.  Why do stars appear as points to us?

Ans: Stars appear as dim points in the night sky. This is due to their very large distances from us.

16.  Why the sun appears like a ball, while other stars appear points to us?

Ans: Almost all the stars are million of times farther away from us as compared to the distance of the sun from us. It is for this reason that the sun appears like a ball to us, but the other stars appear only as points or dots.

17.  Why do, we usually not see the stars during the day?

Ans: The stars are not visible during day-time due to sun’s brightness.

18.  Define the term ‘constellation’.

Ans: A constellation is a group of stars that appear to form some recognisable pattern or shape in the sky.

19.  Why was the concept of constellations important?

Ans: The concept of constellations was important as ancient people were dependent on these stars to find directions and to measure time.

20.  Name some constellations.

Ans: Some constellations are, Ursa Major (Big Dipper), Orion, Ursa Minor (Small Dipper) and Cassiopeia.

21.   Give a short description about Ursa Major.

Ans: i) Ursa Major is seen during the spring, in the early part of night.

ii) Ursa Major is also known as the Great Bear (or Big Dipper).

iii) There are seven prominent stars in Ursa Major.

iv) The two stars, at the top of this constellation, help to locate the Pole Star.

22.  How can we locate the Pole Star with the help of Ursa Major?

Ans: The two stars, at the top of Ursa Major, are called pointers. The line joining those points directs the position of the Pole star (North Star).

23.  In what respects is, the pole star, different from other stars?

Ans:i) The pole star, unlike other stars, appears to remain fixed at one place.

ii) This is so because it lies along the axis of rotation of the earth.

iii) Because of this special feature, this star has been useful to travellers. It defines the North direction.

24.  Write the difference between a planet and a star.

Ans:i) Planets appear like tiny discs whereas stars appear as points.

ii) Stars appear to twinkle. Planets do not twinkle.

iii) Stars appear to be almost stationary. Planets change their relative position with respect to each other.

25.  Planets appear as tiny discs whereas stars appear as points. Why?

Ans: A planet is closer to us than the stars. That is why, planets appear like tiny discs whereas stars appear as points.

26.  Why planets (wandering stars) are so named?

Ans: i) Planets change their relative position with respect to each other.

ii) They appear to move against the background of stationary stars.

iii) This was the reason why ancient people named them as planets i.e. wandering stars.

27.  A star appear to rise four minutes earlier every day. Give reason.

Ans: i) The earth revolves around the sun.

ii) Alongwith this revolution around the sun, the earth also rotates about its own axis.

iii) These two motions of the earth cause the same star to appear to rise four minutes earlier every day.

28.  We see a whole different set of stars in the sky after every six months. Give reason.

Ans: The earth revolves around the sun and, in six months time, moves to the other side of the sun. Therefore, we see a whole different set of stars in the sky after every six months.