Ch8. Body movements
| 1. | Name the following: |
| (a) | The structure by which a cockroach can sense any danger. |
| ans: | Cerci |
| (b) | The hair-like bristles which are present on the underside of an earthworm’s body. |
| ans: | Setae |
| (c) | Places where two or more bones meet. |
| ans: | Joint |
| (d) | The bones in the wrist. |
| ans: | Carpals |
| 2. | State true or false. Correct the false statements. |
| (a) | Animals with backbone are called invertebrates. |
| ans: | False The animals without backbone are called as vertebrates. / The animals with backbone are called as vertebrates. |
| (b) | The human skeleton is made up of 102 bones. |
| ans: | False The human skeleton is made up of 206 bones. |
| (c) | The wings of birds are covered with feathers for flying. |
| ans: | True |
| (d) | The backbone of a fish is flexible. |
| ans: | True |
| 3. | Fill in the blanks: |
| (a) | Cartilage is a tough and elastic substance and is flexible as opposed to bones. |
| (b) | A cockroach as three pair of legs. |
| (c) | Birds have light and hollow bones. |
| (d) | The body of a snake is covered with scales which allow it to slither on the ground. |
| In following questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following: | |
| (A) Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion. (B) Both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. (C) Assertion is true but the Reason is false. (D) Both Assertion and Reason are false. | |
| (a) | Assertion: Snails have four tentacles on their head. Reason: The lower tentacles bear the eyes of the snail. |
| ans: | (D) Both Assertion and Reason are false. |
| (b) | Assertion: The backbone is made up of 33 small bones known as the vertebrae. Reason: Backbone is also known as the vertebral column. |
| ans: | (A) Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion. |
| 1. | Define the following terms: |
| (a) | Locomotion |
| ans: | The act of moving from one place to another is known as locomotion. |
| (b) | Floating ribs |
| ans: | The two bottom pairs of ribs that are not joined to the breastbone or sternum are called floating ribs. |
| 2. | Answer in brief: |
| (a) | What is downstroke? Which two organs are protected by rib cage? |
| ans: | The heart and the lungs are protected by the rib cage. |
| (b) | Explain the terms: (i) upstroke (ii) downstroke |
| ans: | The bird then lifts the wings upwards in preparation for another downstroke and continues. This is termed ‘upstroke’. While flying, a bird first moves its wings down and forward. This lifts the body of the bird in the air. This movement is termed ‘downstroke’. |
| (c) | What is bone marrow? State its function. |
| ans: | The soft and spongy mass inside the bones are called bone marrow. The bone marrow produces blood cells. |
| (d) | State one function of each of the following: |
| (i) Fins in fish | |
| ans: | Fish have pairs of fins which helps in: maintaining balance changing directions |
| (answers may vary) | |
| (ii) Foot in snail | |
| ans: | The foot produces wave-like movements which propel the body of the snail forward. / Foot helps in movement of snail. Produces mucous. |
| (answers may vary) | |
| 3. | Give reasons for the following: |
| (a) | A snail does not get cut if it moves over a sharp razor blade. |
| ans: | Snail does not get cut if it moves over a sharp razor blade due to its muscular foot and, because of the protective and slimy mucous which reduces friction. |
| (b) | Snakes can move very fast. |
| ans: | While moving, the body of a snake curves into many loops and each loop presses against the ground to give a forward push to the body. Making several such loops helps the snake to move very fast. |
| Observe the given diagram and answer the questions that follow. | |
| (a) | Label the parts 1 to 4. |
| ans: | 1- Femur 2- Tibia 3- Fibula 4- Tarsals |
| (b) | List two activities that can be performed by using the lower limbs. |
| ans: | One can walk, run and jump using the lower limbs. |
| Read the following paragraph and answer the following questions: | |
| Sam was hospitalized after falling down while playing in the school. He was immediately rushed to the doctor. He was not able to walk properly due to severe pain in his right leg. Doctor suggested to get an X-ray test done. | |
| (a) | Why doctor advised to take an X-ray image? |
| ans: | X-rays are radiations which can pass through skin and soft tissues but cannot pass through bones. Hence bones can be clearly seen in X-ray image. If any bone may have broken, the doctor would immediately start with the treatment. |
| (b) | Who discovered X-rays? |
| ans: | X-rays were discovered by German physicist Wilhelm Conrad Roentgen. |
Diagram based questions
| Given below is the diagram of a part of human skeleton. Complete the diagram by joining the dots in correct sequence. | |
| Clue: This part of the skeleton system protects the brain. | |
| You discover an unusual new organism in the deep sea and you are studying its skeletal system in your school laboratory aquarium. The organism appears to have a liquid-filled body. The liquid filled in its body is helping it to maintain its shape. (i) What kind of skeletal system does this organism most likely have- exoskeleton or endoskeleton? (ii) Name one animal that have the same type of skeleton system as that of this animal. | |
| ans: | endoskeleton earthworm |
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