🔬 Science Question Papers (EM & TM) 1st Mid Term Test 2024 - Original Question Paper | Tuticorin District | Mr. Amd Ryson (English Medium)

First Mid Term Test - 2024 | Science - Standard X | Solutions

FIRST MID-TERM TEST - 2024

Standard - X

SCIENCE (With Solutions)

Time: 1.30 hrs Marks: 50

Part - I

7 × 1 = 7

I. Answer all the questions.

  1. In which of the following sports is the turning effect of force used?
    • a) Swimming
    • b) Tennis
    • c) Cycling
    • d) Hockey

    Solution

    Answer: c) Cycling

    Explanation: The turning effect of a force is called torque or moment of a force. In cycling, a force is applied to the handlebars to turn the front wheel. This creates a torque that changes the direction of the bicycle.

  2. If the power of a lens is $-4D$, then its focal length is:
    • a) 4m
    • b) -40m
    • c) -0.25m
    • d) -2.5m

    Solution

    Answer: c) -0.25m

    Explanation: The power of a lens (P) is the reciprocal of its focal length (f) in meters. The formula is $P = 1/f$.

    Given, Power (P) = -4 Dioptre (D).

    Therefore, focal length (f) = $1/P = 1 / (-4) = -0.25$ m.

    The negative sign indicates that it is a concave (diverging) lens.

  3. In the nucleus of $_{20}\text{Ca}^{40}$, there are:
    • a) 20 protons and 40 neutrons
    • b) 20 protons and 20 neutrons
    • c) 20 protons and 40 electrons
    • d) 40 protons and 20 electrons

    Solution

    Answer: b) 20 protons and 20 neutrons

    Explanation: For an element represented as $_{Z}\text{X}^{A}$:

    • Z is the Atomic Number, which equals the number of protons. Here, Z = 20 for Calcium (Ca). So, there are 20 protons.
    • A is the Mass Number, which equals the sum of protons and neutrons. Here, A = 40.
    • Number of neutrons = Mass Number (A) - Atomic Number (Z) = $40 - 20 = 20$.

    Thus, the nucleus contains 20 protons and 20 neutrons.

  4. Which of the following alloys is used to make parts of an aircraft?
    • a) Duralumin
    • b) Magnalium
    • c) Nickel steel
    • d) Stainless Steel

    Solution

    Answer: a) Duralumin

    Explanation: Duralumin is an alloy primarily composed of aluminum (about 95%), copper (4%), magnesium (0.5%), and manganese (0.5%). It is known for being lightweight, strong, and resistant to corrosion, making it ideal for manufacturing aircraft bodies and parts.

  5. Casparian strips are present in the __________ of the root.
    • a) Cortex
    • b) Pith
    • c) Pericycle
    • d) Endodermis

    Solution

    Answer: d) Endodermis

    Explanation: The endodermis is the innermost layer of the cortex in a plant root. Its cells have Casparian strips, which are bands of waterproof, waxy material (suberin). These strips block the passive flow of water and solutes, forcing them to pass through the living plasma membrane of the endodermal cells, thus regulating their entry into the vascular cylinder (xylem and phloem).

  6. The brain of a leech lies above the:
    • a) Mouth
    • b) Buccal cavity
    • c) Pharynx
    • d) Crop

    Solution

    Answer: c) Pharynx

    Explanation: The central nervous system of a leech consists of a nerve ring and a ventral nerve cord. The "brain" is the supra-pharyngeal ganglion, which is part of the nerve ring that encircles the pharynx. Therefore, the brain lies above the pharynx.

  7. An example of a myogenic heartbeat is found in:
    • a) Mollusca
    • b) Annelids
    • c) Arthropods
    • d) Porifera

    Solution

    Answer: a) Mollusca

    Explanation: A myogenic heartbeat is one where the cardiac impulse (the signal to contract) originates from specialized muscle cells within the heart itself, not from external nerve stimulation. This type of heartbeat is characteristic of all vertebrates and some invertebrates, including molluscs. In contrast, many annelids and arthropods have a neurogenic heartbeat, which is initiated by nerve impulses. Porifera (sponges) lack a circulatory system and a heart.

Part - II

5 × 2 = 10

II. Answer any 5 of the following questions. (Question No. 14 is compulsory)

  1. Define inertia. Give its classification.

    Solution

    Inertia: Inertia is the inherent property of a body to resist any change in its state of rest or state of uniform motion, unless it is acted upon by an external unbalanced force.

    Classification of Inertia: Inertia is classified into three types:

    1. Inertia of Rest: The resistance of a body to change its state of rest. (e.g., A passenger falls backward when a bus suddenly starts).
    2. Inertia of Motion: The resistance of a body to change its state of uniform motion. (e.g., An athlete runs a certain distance after crossing the finishing line).
    3. Inertia of Direction: The resistance of a body to change its direction of motion. (e.g., A passenger leans sideways when a bus takes a sharp turn).
  2. Define Atomicity. Give an example.

    Solution

    Atomicity: Atomicity is defined as the total number of atoms present in one molecule of an element, compound, or substance.

    Examples:

    • The atomicity of an Oxygen molecule ($O_2$) is 2 (Diatomic).
    • The atomicity of an Ozone molecule ($O_3$) is 3 (Triatomic).
    • The atomicity of a Phosphorus molecule ($P_4$) is 4 (Tetra-atomic).
  3. What is rust? Give the equation for the formation of rust.

    Solution

    Rust: Rust is a reddish-brown, flaky substance that forms on the surface of iron or its alloys when they are exposed to oxygen and moisture for a prolonged period. Chemically, it is hydrated ferric oxide ($Fe_2O_3 \cdot xH_2O$).

    Equation for Rust Formation:

    When iron comes into contact with oxygen in the presence of water (moisture), it undergoes oxidation to form rust.

    $4Fe + 3O_2 + xH_2O \rightarrow 2Fe_2O_3 \cdot xH_2O$

    (Iron + Oxygen + Water $\rightarrow$ Hydrated Ferric Oxide (Rust))

  4. Draw the following diagram and label the parts.
    [ Diagram of a Bacterial Cell to be inserted here ]

    Solution

    A diagram of a bacterial cell should be drawn, and the following essential parts should be labeled:

    Diagram of a Bacterial Cell

    Image Credit: Wikipedia Commons

    Key Labels:

    • Capsule: Outermost protective layer.
    • Cell Wall: Provides structural support.
    • Plasma Membrane: Regulates the entry and exit of substances.
    • Cytoplasm: The jelly-like substance filling the cell.
    • Ribosomes: Sites of protein synthesis.
    • Nucleoid (Circular DNA): The region containing the genetic material.
    • Flagellum: A long, whip-like tail used for movement.
    • Pili (or Fimbriae): Hair-like appendages on the surface used for attachment.
  5. Why are minerals in plants not lost when a leaf falls?

    Solution

    Minerals in plants are not lost when a leaf falls due to a process called nutrient translocation or reabsorption.

    Before a leaf undergoes senescence (aging) and abscission (falling), the plant actively breaks down complex molecules within the leaf. Essential mobile nutrients like nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) are transported out of the dying leaf and moved to other growing parts of the plant, such as young leaves, stems, or storage organs. This efficient recycling mechanism ensures that valuable minerals are conserved by the plant and not lost with the discarded leaves.

  6. Differentiate between voluntary and involuntary actions.

    Solution

    Feature Voluntary Actions Involuntary Actions
    Control Actions performed under our conscious control or will. Actions that occur without our conscious control or will.
    Nervous System Controlled by the cerebrum (forebrain). Controlled by the medulla oblongata (hindbrain) and spinal cord.
    Muscles Involved Involve skeletal muscles (e.g., muscles of limbs, hands). Involve smooth muscles (e.g., in the gut) and cardiac muscles (in the heart).
    Examples Walking, writing, eating, talking. Heartbeat, breathing, digestion, blinking (reflex).
  7. A beam of light passing through a diverging lens of focal length 0.3m appears to be focused at a distance of 0.2m behind the lens. Find the position of the object.

    Solution

    We need to use the lens formula to find the position of the object (u).

    The lens formula is: $ \frac{1}{f} = \frac{1}{v} - \frac{1}{u} $

    Given values (using sign convention):

    • Type of lens: Diverging lens (Concave lens).
    • Focal length (f): For a diverging lens, the focal length is negative. So, $f = -0.3$ m.
    • Image distance (v): A diverging lens always forms a virtual image on the same side as the object. By convention, this distance is negative. So, $v = -0.2$ m.

    Calculation:

    Substitute the values into the lens formula:

    $ \frac{1}{-0.3} = \frac{1}{-0.2} - \frac{1}{u} $

    To find $\frac{1}{u}$, we rearrange the equation:

    $ \frac{1}{u} = \frac{1}{-0.2} - \frac{1}{-0.3} $

    $ \frac{1}{u} = -\frac{1}{0.2} + \frac{1}{0.3} $

    To subtract the fractions, find a common denominator (0.6):

    $ \frac{1}{u} = -\frac{3}{0.6} + \frac{2}{0.6} $

    $ \frac{1}{u} = \frac{-3 + 2}{0.6} = \frac{-1}{0.6} $

    Therefore, the object distance $u$ is:

    $ u = -0.6 $ m

    Answer: The position of the object is 0.6 m in front of the lens. The negative sign indicates that the object is placed on the same side from which the light is coming, as per standard sign convention.

Part - III

3 × 4 = 12

III. Answer any 3 of the following questions. (Question No. 19 is compulsory)

  1. a) What is the power of accommodation of the eye? (2)
    b) What are the causes of 'Myopia'? (2)

    Solution

    a) Power of Accommodation of the Eye

    The power of accommodation is the ability of the eye to automatically adjust its focal length to see objects clearly at varying distances. This is achieved by the action of the ciliary muscles, which change the curvature (and thus the converging power) of the eye lens.

    b) Causes of Myopia

    Myopia, or near-sightedness, is a condition where a person can see nearby objects clearly but distant objects appear blurry. This occurs because the light from distant objects is focused in front of the retina instead of on it. The main causes are:

    1. Elongation of the eyeball: The distance between the eye lens and the retina becomes too large.
    2. Increased curvature of the eye lens: The eye lens becomes too convex (thick), causing it to have a shorter focal length and converge light too strongly.
  2. a) Name the three basic tissue systems in flowering plants. (2)
    b) Why must the light-dependent reaction occur before the light-independent reaction? (2)

    Solution

    a) Three Basic Tissue Systems in Flowering Plants

    1. Dermal Tissue System: The outer protective covering of the plant (e.g., epidermis, cuticle).
    2. Ground Tissue System: Makes up the bulk of the plant body and performs functions like photosynthesis, storage, and support (e.g., parenchyma, collenchyma, sclerenchyma).
    3. Vascular Tissue System: Responsible for the transport of water, minerals, and food (e.g., xylem and phloem).

    b) Why Light-Dependent Reactions Must Precede Light-Independent Reactions

    The light-dependent reactions must occur first because they produce the essential energy carriers—ATP (Adenosine Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate)—that are required to power the light-independent reactions (Calvin Cycle). The light-independent reactions use the chemical energy stored in ATP and the reducing power of NADPH to convert carbon dioxide ($CO_2$) into glucose (sugar). Without the products of the light-dependent stage, the second stage cannot proceed.

  3. How does locomotion take place in a leech?

    Solution

    A leech exhibits two types of locomotion: looping (or crawling) and swimming.

    Looping / Crawling Movement:

    This is the primary mode of movement on a solid surface and involves the use of its two suckers and body muscles.

    1. Fixation: The leech first fixes its posterior sucker firmly onto the substratum.
    2. Contraction & Elongation: The longitudinal muscles of the body contract, causing the body to shorten, while the circular muscles relax. This pushes the anterior end forward.
    3. Anterior Fixation: The anterior sucker is then fixed to the new position on the surface.
    4. Release and Arching: The posterior sucker is released from its original position. Now, the circular muscles contract and the longitudinal muscles relax, causing the body to become shorter and thicker, and arch up like a loop.
    5. Forward Movement: The posterior end is brought forward, close to the anterior end, and the posterior sucker is fixed again.

    This cycle of fixing, extending, and arching is repeated, allowing the leech to "crawl" or "loop" forward.

    Swimming Movement: In water, leeches swim by performing rapid undulating (wave-like) movements of their body.

  4. Enumerate the functions of blood.

    Solution

    Blood is a vital fluid connective tissue that performs numerous essential functions in the body, which can be categorized as follows:

    1. Transport:
      • Respiratory Gases: Transports oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs.
      • Nutrients: Carries digested food materials like glucose, amino acids, and fatty acids from the intestine to all body cells.
      • Hormones: Transports hormones from endocrine glands to their target organs.
      • Waste Products: Carries metabolic wastes like urea and uric acid from the tissues to the excretory organs (kidneys).
    2. Regulation:
      • Body Temperature: Helps maintain a constant body temperature by distributing heat throughout the body.
      • pH Balance: Maintains the acid-base balance of the body fluids through its buffering systems.
      • Water Balance: Regulates the water content of cells and tissues.
    3. Protection:
      • Immunity: White Blood Cells (WBCs) defend the body against pathogens like bacteria and viruses.
      • Clotting: Platelets and clotting factors in the plasma prevent excessive blood loss by forming a clot at the site of an injury.
  5. Calculate the percentage composition of each element in Calcium Carbonate ($CaCO_3$). (Atomic mass: C-12, O-16, Ca-40)

    Solution

    To calculate the percentage composition, we first need to find the molar mass of Calcium Carbonate ($CaCO_3$).

    Step 1: Calculate the Molar Mass of $CaCO_3$

    Molar Mass of $CaCO_3$ = (Atomic mass of Ca) + (Atomic mass of C) + 3 × (Atomic mass of O)

    $ = 40 + 12 + 3 \times 16 $

    $ = 40 + 12 + 48 $

    $ = 100 $ g/mol

    Step 2: Calculate the Percentage Composition of Each Element

    The formula for percentage composition is:

    $ \text{Percentage of an element} = \frac{\text{Total mass of the element in the compound}}{\text{Molar mass of the compound}} \times 100 $

    a) Percentage of Calcium (Ca):

    $ \% \text{Ca} = \frac{\text{Mass of Ca}}{\text{Molar Mass of } CaCO_3} \times 100 = \frac{40}{100} \times 100 = 40\% $

    b) Percentage of Carbon (C):

    $ \% \text{C} = \frac{\text{Mass of C}}{\text{Molar Mass of } CaCO_3} \times 100 = \frac{12}{100} \times 100 = 12\% $

    c) Percentage of Oxygen (O):

    $ \% \text{O} = \frac{\text{Mass of O}}{\text{Molar Mass of } CaCO_3} \times 100 = \frac{48}{100} \times 100 = 48\% $

    Answer: The percentage composition is Calcium: 40%, Carbon: 12%, and Oxygen: 48%.

    (Check: $40\% + 12\% + 48\% = 100\%$).

Part - IV

3 × 7 = 21

IV. Answer all the questions.

  1. a) i) State Newton's second law of motion. (2)

        ii) Deduce the equation of force using Newton's Second Law of motion. (5)

    Solution a)

    i) Newton's Second Law of Motion

    Newton's second law of motion states that "the rate of change of momentum of a body is directly proportional to the external unbalanced force applied on it, and the change in momentum takes place in the direction of the force."

    ii) Deduction of the Equation of Force ($F=ma$)

    Let's consider an object of mass 'm' moving with an initial velocity 'u'. An external unbalanced force 'F' is applied on it for a time 't', which changes its velocity to 'v'.

    1. Initial Momentum ($p_i$): The initial momentum of the object is the product of its mass and initial velocity.

      $p_i = mu$

    2. Final Momentum ($p_f$): The final momentum of the object is the product of its mass and final velocity.

      $p_f = mv$

    3. Change in Momentum ($\Delta p$): The change in momentum is the difference between the final and initial momentum.

      $\Delta p = p_f - p_i = mv - mu = m(v-u)$

    4. Rate of Change of Momentum: This is the change in momentum per unit time.

      Rate of change of momentum = $\frac{\Delta p}{t} = \frac{m(v-u)}{t}$

    5. Applying Newton's Second Law: According to the law, the applied force (F) is directly proportional to the rate of change of momentum.

      $ F \propto \frac{m(v-u)}{t} $

    6. Introducing Acceleration: We know that acceleration ($a$) is the rate of change of velocity, so $ a = \frac{v-u}{t} $. Substituting this into the equation:

      $ F \propto ma $

    7. Formulating the Equation: To turn the proportionality into an equation, we introduce a constant of proportionality, 'k'.

      $ F = k \cdot ma $

      The value of the constant 'k' is chosen to be 1 in the SI system of units (One unit of force is defined as the amount that produces one unit of acceleration in a body of one unit mass). So, k=1.
    8. Final Equation:

      Therefore, the equation for force is:

      $ F = ma $

    [OR]

    b) Differentiate between the eye defects: Myopia and Hypermetropia.

    Solution b)

    The following table differentiates between Myopia and Hypermetropia:

    Feature Myopia (Near-sightedness) Hypermetropia (Far-sightedness)
    Definition A defect where a person can see nearby objects clearly but distant objects appear blurry. A defect where a person can see distant objects clearly but nearby objects appear blurry.
    Image Formation The image of a distant object is formed in front of the retina. The image of a nearby object is formed behind the retina.
    Causes
    • Elongation of the eyeball.
    • Increased curvature (thickening) of the eye lens.
    • Focal length of the eye lens is too short.
    • Shortening of the eyeball.
    • Decreased curvature (thinning) of the eye lens.
    • Focal length of the eye lens is too long.
    Far Point The far point is closer than infinity. The near point is farther than 25 cm.
    Correction Corrected by using a concave lens (diverging lens) of appropriate power. Corrected by using a convex lens (converging lens) of appropriate power.
    Diagrammatic Effect The concave lens diverges the incoming light rays before they enter the eye, so the eye lens can focus them correctly on the retina. The convex lens converges the incoming light rays before they enter the eye, helping the eye lens to focus them on the retina.

  2. a) i) Give the salient features of "Modern Atomic Theory". (5)

        ii) Calculate the number of moles in 27g of Aluminium. (2)

    Solution a)

    i) Salient Features of Modern Atomic Theory

    The Modern Atomic Theory, which evolved from Dalton's atomic theory, includes the following key features:

    1. Atom is no longer indivisible: An atom is now known to be divisible and consists of subatomic particles: protons, neutrons, and electrons.
    2. Isotopes: Atoms of the same element can have different atomic masses. These are called isotopes (e.g., Chlorine-35 and Chlorine-37). This contradicts Dalton's postulate that all atoms of an element are identical in mass.
    3. Isobars: Atoms of different elements can have the same atomic mass. These are called isobars (e.g., $_{18}Ar^{40}$ and $_{20}Ca^{40}$).
    4. Atom is the smallest particle that takes part in a chemical reaction: While an atom is divisible, it remains the smallest unit that participates in chemical reactions.
    5. Mass can be converted into energy: The mass of an atom can be converted into energy, as described by Einstein's equation, $E=mc^2$. This means that mass is not always conserved in nuclear reactions.
    6. Atoms may not combine in simple whole-number ratios: In some cases, particularly in complex organic and non-stoichiometric compounds, the ratio of atoms is not always simple (e.g., in sucrose, $C_{12}H_{22}O_{11}$).

    ii) Calculation of Moles in 27g of Aluminium

    The formula to calculate the number of moles is:

    $ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molar mass}} $

    • Given mass of Aluminium (Al): 27 g
    • Molar mass (or atomic mass) of Aluminium (Al): 27 g/mol

    Substituting the values into the formula:

    $ \text{Number of moles} = \frac{27 \text{ g}}{27 \text{ g/mol}} = 1 \text{ mole} $

    Answer: There is 1 mole in 27g of Aluminium.

    [OR]

    b) i) Define Corrosion. (2)

        ii) What are the types of Corrosion? (2)

        iii) What are the methods of preventing corrosion? (3)

    Solution b)

    i) Definition of Corrosion

    Corrosion is a natural process of gradual degradation or destruction of metals and their alloys by chemical or electrochemical reaction with their environment. It involves the conversion of a refined metal into a more chemically stable form, such as its oxide, hydroxide, or sulfide. The most common example is the rusting of iron.

    ii) Types of Corrosion

    Based on the mechanism and environment, corrosion can be broadly classified into two main types:

    1. Dry Corrosion (or Chemical Corrosion): This occurs in the absence of moisture, typically at high temperatures. The metal surface reacts directly with atmospheric gases like oxygen, nitrogen, sulfur dioxide, etc., to form an oxide layer.
    2. Wet Corrosion (or Electrochemical Corrosion): This is the more common type and occurs in the presence of moisture or an electrolyte. It involves the formation of electrochemical cells on the surface of the metal, leading to oxidation (at the anode) and reduction (at the cathode) reactions. Rusting of iron is a prime example.

    iii) Methods of Preventing Corrosion

    Corrosion can be prevented or controlled using several methods:

    • Alloying: Mixing a metal with other metals or non-metals to create an alloy that is more resistant to corrosion. For example, stainless steel (an alloy of iron, chromium, and nickel) is highly resistant to rust.
    • Surface Coating: Applying a protective layer on the metal surface to isolate it from the environment.
      • Painting: Applying a coat of paint.
      • Oiling/Greasing: Applying a layer of oil or grease.
      • Electroplating: Coating the metal with a less reactive metal (like chromium or nickel) using electricity.
      • Galvanization: Coating iron or steel with a layer of zinc. Zinc is more reactive and corrodes preferentially, protecting the iron (this is a form of sacrificial protection).
    • Sacrificial Protection (Cathodic Protection): Connecting the metal to be protected (e.g., an iron pipeline) to a more reactive metal (like magnesium or zinc). The more reactive metal acts as the anode and gets corroded, "sacrificing" itself to protect the main metal.

  3. a) i) How does the light-dependent reaction differ from the light-independent reaction? What are the reactants and end products in each? (5)

        ii) Give the importance of transpiration. (2)

    Solution a)

    i) Differences between Light-Dependent and Light-Independent Reactions

    Feature Light-Dependent Reaction (Hill Reaction) Light-Independent Reaction (Calvin Cycle / Biosynthetic Phase)
    Location Occurs in the thylakoid membranes (Grana) of the chloroplasts. Occurs in the stroma of the chloroplasts.
    Light Requirement Requires direct light energy. Does not require direct light energy (but depends on the products of the light reaction).
    Primary Function To capture light energy and convert it into chemical energy (ATP and NADPH). To use the chemical energy (ATP and NADPH) to synthesize glucose from carbon dioxide.
    Reactants (Inputs) Light, Water ($H_2O$), ADP, NADP⁺ Carbon Dioxide ($CO_2$), ATP, NADPH
    End Products (Outputs) Oxygen ($O_2$), ATP, NADPH Glucose ($C_6H_{12}O_6$), ADP, NADP⁺

    ii) Importance of Transpiration

    Transpiration, the loss of water vapor from plants, is often called a "necessary evil" because it has several crucial benefits:

    • Creates Transpirational Pull: The evaporation of water from leaves creates a suction force (tension) that pulls water and dissolved minerals up from the roots through the xylem to the rest of the plant.
    • Absorption and Transport of Minerals: The continuous flow of water due to transpiration helps in the absorption and distribution of essential minerals from the soil.
    • Cooling Effect: Evaporation of water from the leaf surface helps to cool the plant, preventing heat damage, especially in warm climates.
    • Maintains Turgidity: By regulating water content, it helps to keep plant cells turgid, which is essential for maintaining the shape and structure of the plant.
    [OR]

    b) i) Classify neurons based on their structure. (4)

        ii) "A" is a cylindrical structure that begins from the lower end of the medulla and extends downwards. It is enclosed in a bony cage "B" and covered by membranes "C". As many as "D" pairs of nerves arise from the structure "A". (3)

    a) What is A?
    b) Name the bony cage 'B' and membranes 'C'.
    c) How many is 'D'?

    Solution b)

    i) Classification of Neurons Based on Structure

    Neurons (nerve cells) are classified into three main types based on the number of processes (axons and dendrites) that extend from the cell body (cyton):

    1. Unipolar Neuron: Has only one process arising from the cyton, which acts as both an axon and a dendrite. These are typically found in the nervous systems of invertebrates and in the embryonic stage of vertebrates.
    2. Bipolar Neuron: Has two processes extending from the cyton—one axon and one dendrite. They are found in sensory organs like the retina of the eye and the olfactory epithelium of the nasal cavity.
    3. Multipolar Neuron: Has a single axon and multiple dendrites extending from the cyton. This is the most common type of neuron in the central nervous system of vertebrates, including the brain and spinal cord.

    ii) Identifying the Structures

    This is a riddle describing the spinal cord and its related structures.

    a) What is A?

    A is the Spinal Cord. It is a long, cylindrical structure that extends from the medulla oblongata of the brainstem.

    b) Name the bony cage 'B' and membranes 'C'.

    • B (the bony cage) is the Vertebral Column (or backbone).
    • C (the membranes) are the Meninges (specifically, the dura mater, arachnoid mater, and pia mater that cover the spinal cord).

    c) How many is 'D'?

    D represents the number of pairs of spinal nerves, which is 31 pairs.

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