1. The continuous circulation of body fluids in a multicellular animal is primarily required to:
ⓐ. maintain body shape without exchanging materials
ⓑ. deliver essential substances and remove wastes
ⓒ. produce every nutrient inside each body cell
ⓓ. isolate tissues from changes in their surroundings
Correct Answer: deliver essential substances and remove wastes
Explanation: Cells in a multicellular body are not all directly exposed to the external environment. They continuously consume oxygen and nutrients, receive hormones and other useful substances, and release carbon dioxide and metabolic wastes. A circulating fluid connects distant exchange or processing surfaces with individual tissues, allowing useful materials to reach cells and unwanted products to be carried away. The need is continuous, since cellular metabolism also continues. Internal transport is not merely structural support, and it does not make every cell self-sufficient. Its central role is coordinated delivery and removal across distances that direct contact with environmental water cannot cover in a complex body.
2. Suppose a transport fluid continues to supply oxygen and nutrients normally, but its ability to carry metabolic wastes away from tissues is lost. The earliest general consequence would be:
ⓐ. complete replacement of internal transport by diffusion
ⓑ. immediate conversion of tissue cells into blood cells
ⓒ. uninterrupted cell function with no internal change
ⓓ. accumulation of wastes around metabolically active cells
Correct Answer: accumulation of wastes around metabolically active cells
Explanation: Internal transport has two complementary directions: useful substances move toward cells, while carbon dioxide and other metabolic wastes move away from them. Preserving only the delivery side does not complete the transport requirement. Metabolically active cells would continue producing waste, but the defective fluid could no longer remove it efficiently, so the local chemical environment would progressively become unfavourable. Direct diffusion might still occur over short distances, yet it cannot replace organised transport throughout a large body. The changed condition isolates waste removal, making waste accumulation the most immediate system-wide effect even though nutrient and oxygen delivery initially remains functional. Continued accumulation would eventually interfere with normal cellular activity even before the supply side of transport itself failed. Continued production without organised removal shifts the local chemical balance first, before later cellular damage or failure of nutrient delivery develops.
3. Consider the following statements about transport strategies in animals.
I. Some simple organisms circulate environmental water through body cavities.
II. Complex organisms generally use specialised internal body fluids.
III. Increasing body complexity removes the need for material transport.
IV. Both strategies can assist delivery and waste removal.
ⓐ. I, II and IV only
ⓑ. I and III only
ⓒ. II and III only
ⓓ. I, II, III and IV
Correct Answer: I, II and IV only
Explanation: A simple body plan may allow environmental water moving through a cavity to come sufficiently close to many cells, supporting exchange without a highly specialised internal circulatory fluid. In a larger and more complex organism, numerous cells lie far from the external environment, so specialised body fluids provide an internal transport link. Complexity increases rather than removes the need to move substances over distance. The two strategies differ in organisation, but they serve related biological purposes: supplying essential materials and carrying away wastes. The valid set includes the statements describing these two arrangements and their shared transport role, while excluding the claim that complexity eliminates transport. The strategy changes with body organisation, but the basic cellular demands for input and waste removal remain.
4. Study the three transport models.
| Model | Transport arrangement |
|---|
| P | Environmental water moves through a body cavity and contacts many cells |
| Q | A specialised internal fluid links exchange surfaces with distant tissues |
| R | Cells receive neither environmental water flow nor an internal transport medium |
Which interpretation is biologically sound?
ⓐ. P and R suit complex organisation, whereas Q supplies only cells directly exposed to environmental water
ⓑ. Q and R provide equivalent long-distance transport, whereas P cannot support exchange in any simple organism
ⓒ. P can suit a simple organisation, Q suits a complex organisation, and R cannot sustain continuous exchange
ⓓ. P, Q and R remain equally effective even when most cells lie far from an exchange surface
Correct Answer: P can suit a simple organisation, Q suits a complex organisation, and R cannot sustain continuous exchange
Explanation: Model P brings environmental water into a body cavity, shortening the distance between the external medium and many cells. Such an arrangement can be adequate in relatively simple organisms. Model Q adds a specialised internal fluid that connects exchange surfaces with tissues located farther away, which is more suitable for a complex multicellular body. Model R provides neither route. Active cells still require continuous input of useful substances and removal of wastes, so complete absence of a transport medium cannot support sustained exchange. Body organisation and transport distance determine whether environmental water flow is sufficient or a specialised internal fluid is required. The decisive issue is whether the arrangement reduces exchange distance and provides a continuous route. A specialised internal fluid becomes especially useful when many cells cannot contact circulating environmental water directly.
5. Assertion: Blood is classified as a specialised connective tissue.
Reason: Complex organisms use internal body fluids to transport materials.
ⓐ. Assertion and Reason are true, and Reason correctly explains Assertion
ⓑ. Assertion and Reason are true, but Reason does not correctly explain Assertion
ⓒ. Assertion is true and Reason is false, so Reason cannot explain Assertion
ⓓ. Assertion is false and Reason is true, so Reason cannot explain Assertion
Correct Answer: Assertion and Reason are true, but Reason does not correctly explain Assertion
Explanation: The assertion is true: blood is a specialised connective tissue whose cells and cell fragments are suspended in a fluid matrix. The reason is also true, since complex organisms rely on internal fluids for transport across substantial distances. However, the transport requirement alone does not establish why blood belongs to the connective-tissue category. That classification depends on its organisation as formed elements dispersed in an extracellular matrix, with the matrix represented by plasma. The reason describes an important function of blood and other body fluids, whereas the assertion concerns tissue classification. They are related ideas, but the stated reason does not supply the defining structural basis of the assertion. A correct explanation of the classification would need to mention the extracellular matrix and the formed elements suspended within it.
6. Blood is composed of:
ⓐ. plasma with suspended formed elements
ⓑ. serum with suspended formed elements
ⓒ. lymph with circulating tissue cells
ⓓ. plasma containing only clotting factors
Correct Answer: plasma with suspended formed elements
Explanation: Blood has two broad components. Plasma is the fluid matrix, and the formed elements suspended in it are erythrocytes, leucocytes and platelets. This part-and-matrix arrangement supports the description of blood as a specialised connective tissue. Serum is related to plasma but lacks clotting factors, so it is not the normal fluid matrix of circulating whole blood. Lymph is another body fluid formed from tissue fluid after entry into lymphatic vessels. Describing blood as only water and clotting factors also omits its proteins, transported solutes and formed elements. The complete basic composition is a fluid plasma phase carrying the formed elements.
7. A biological material contains an abundant non-living fluid matrix in which cells and cell fragments remain suspended, and it transports substances between distant body regions. Its most appropriate tissue classification is:
ⓐ. epithelial tissue with a continuous cellular sheet
ⓑ. muscular tissue with contractile fibres
ⓒ. nervous tissue with impulse-conducting cells
ⓓ. specialised connective tissue with a fluid matrix
Correct Answer: specialised connective tissue with a fluid matrix
Explanation: Connective tissues characteristically contain cells separated by an extracellular matrix. In blood, the matrix is unusual in being fluid rather than solid or fibrous. Erythrocytes and leucocytes are cells, while platelets are cell fragments; all remain suspended in plasma and are transported throughout the body. The stated evidence combines structure with function: a fluid extracellular matrix and dispersed formed elements enable long-distance transport. Epithelial tissue is organised mainly as closely packed sheets, muscle is defined by contraction, and nervous tissue by rapid impulse conduction. The matrix-and-formed-element arrangement identifies blood as a specialised connective tissue rather than merely a fluid mixture. Its transport function follows from this organisation, but the classification itself rests on the relationship between matrix and suspended elements.
8. A sample contains \(200\,\text{mL}\) of whole blood. Using the approximate normal plasma proportion, the plasma volume is:
ⓐ. \(90\,\text{mL}\)
ⓑ. \(55\,\text{mL}\)
ⓒ. \(110\,\text{mL}\)
ⓓ. \(145\,\text{mL}\)
Correct Answer: \(110\,\text{mL}\)
Explanation: The given whole-blood volume is \(200\,\text{mL}\), and plasma constitutes nearly \(55\%\) of blood. The required plasma volume is found by applying this fraction to the total sample:
\[\text{Plasma volume}=200\,\text{mL}\times\frac{55}{100}=110\,\text{mL}\]
The calculation refers to plasma as a proportion of whole blood, not to the percentage of water within plasma. The remaining portion contains the formed elements suspended in the plasma. Since the stated proportion is approximate, \(110\,\text{mL}\) is an expected reference value rather than an exact value for every individual sample. The biological meaning is that a little over half of normal blood volume is its fluid matrix. The complementary volume in this simplified sample is about \(90\,\text{mL}\), representing the suspended formed-element portion. This second value is a useful check that the two broad fractions account for the original \(200\,\text{mL}\) total.
9. Consider the following statements about plasma.
I. It is the fluid matrix of blood.
II. Nearly \(55\%\) refers to its approximate share of whole blood.
III. Its straw colour describes the appearance of plasma itself.
IV. The value \(55\%\) means that plasma contains only \(55\%\) water.
ⓐ. I, II and III only
ⓑ. I and IV only
ⓒ. II, III and IV only
ⓓ. I, II, III and IV
Correct Answer: I, II and III only
Explanation: Plasma is the fluid matrix in which the formed elements of blood remain suspended, and it normally forms nearly \(55\%\) of whole blood. It is described as a straw-coloured, viscous fluid, so the colour statement applies to plasma rather than to the cellular fraction. The fourth statement confuses two different percentage levels. The \(55\%\) value compares plasma with whole blood, whereas the water percentage is calculated within plasma and is much higher. Keeping the denominator clear prevents a common error: a component can form a little over half of whole blood while still being composed mainly of water. The first three statements preserve these distinct relations. The same component can be described at two levels: its share of whole blood and the composition within that component. Mixing those reference totals produces an incorrect interpretation.
10. In a blood sample, the absolute volume of formed elements remains unchanged while some plasma is removed. Compared with the original sample, the new sample will show:
ⓐ. a lower relative share of formed elements and a higher share of plasma
ⓑ. a higher relative share of formed elements and a lower share of plasma
ⓒ. unchanged relative shares of plasma and formed elements
ⓓ. equal decreases in the relative shares of both components
Correct Answer: a higher relative share of formed elements and a lower share of plasma
Explanation: Percent composition depends on each component relative to the new total volume. The amount of formed elements is unchanged, but removal of plasma reduces both the plasma amount and the total sample volume. Formed elements now occupy a larger fraction of that smaller total, while plasma occupies a smaller fraction. No new formed elements need to be produced for their percentage to rise; the change is relative. This distinction separates absolute amount from proportional composition. The usual value of nearly \(55\%\) plasma describes an approximate normal sample, not a fixed fraction that must remain unchanged after one component is selectively removed. This proportional change would occur even though the actual quantity of formed elements had not increased.
11. Evaluate the following statements about the composition of plasma.
I. Water forms approximately \(90\text{–}92\%\) of plasma.
II. Proteins contribute approximately \(6\text{–}8\%\) of plasma.
III. These percentages describe the composition of whole blood directly.
IV. A small remaining fraction contains other dissolved substances.
ⓐ. I and III only
ⓑ. II and III only
ⓒ. I, III and IV only
ⓓ. I, II and IV only
Correct Answer: I, II and IV only
Explanation: Plasma itself contains approximately \(90\text{–}92\%\) water and \(6\text{–}8\%\) proteins. These values use plasma as the reference total, not whole blood. A small residual fraction contains ions, glucose, amino acids, lipids and other substances being transported. The percentages are approximate ranges, so they need not add to one fixed value in every sample, but they describe water as overwhelmingly predominant and proteins as the next major listed fraction. The third statement changes the denominator from plasma to whole blood and is not valid. The correct combination preserves both the numerical ranges and the level of biological organisation to which they apply. It also leaves room for the minor solute fraction that completes plasma composition without treating approximate ranges as rigid constants.
12. In a simplified \(100\,\text{mL}\) plasma sample, water accounts for \(91\%\) and proteins for \(7\%\). The volume assigned to other plasma solutes in this model is:
ⓐ. \(1\,\text{mL}\)
ⓑ. \(7\,\text{mL}\)
ⓒ. \(2\,\text{mL}\)
ⓓ. \(9\,\text{mL}\)
Correct Answer: \(2\,\text{mL}\)
Explanation: The sample total is \(100\,\text{mL}\). Water contributes \(91\,\text{mL}\) and proteins contribute \(7\,\text{mL}\) under the simplified percentage model. The remaining volume is:
\[\text{Other solutes}=100\,\text{mL}-91\,\text{mL}-7\,\text{mL}=2\,\text{mL}\]
This residual category represents substances such as ions, glucose, amino acids and lipids in transit. The calculation is biologically useful only when the denominator remains the plasma sample itself. It does not estimate the composition of whole blood, and it does not imply that every real plasma sample has exactly these values. The result fits the picture of plasma as mainly water, with proteins and a smaller dissolved-solute fraction. A useful reporting check is \(91+7+2=100\), confirming that all categories in the simplified model account for the complete plasma sample. The arithmetic supports composition reasoning rather than representing a new physiological constant.
13. In a simplified proportional model, plasma forms \(0.55\) of whole blood and water forms \(0.90\text{–}0.92\) of plasma. Which expression estimates the fraction of whole blood represented by plasma water?
ⓐ. \(0.55\times(0.90\text{–}0.92)\approx0.495\text{–}0.506\)
ⓑ. \(0.45\times(0.90\text{–}0.92)\approx0.405\text{–}0.414\)
ⓒ. \(0.55+(0.90\text{–}0.92)\approx1.45\text{–}1.47\)
ⓓ. \(\frac{0.55}{0.90\text{–}0.92}\approx0.598\text{–}0.611\)
Correct Answer: \(0.55\times(0.90\text{–}0.92)\approx0.495\text{–}0.506\)
Explanation: This is a nested proportion. First, plasma accounts for \(0.55\) of whole blood. Within that plasma portion, water accounts for \(0.90\text{–}0.92\). To obtain the fraction of the original whole-blood volume represented by plasma water, the two fractions are multiplied:
\[\text{Plasma-water fraction}=0.55\times(0.90\text{–}0.92)=0.495\text{–}0.506\]
The estimated range is about \(49.5\text{–}50.6\%\) of whole blood under the simplified model. Adding the fractions would combine quantities with different reference totals, while using the formed-element fraction changes the component being measured. The calculation also illustrates why plasma can be only about \(55\%\) of blood yet water in plasma can exceed \(90\%\). The first percentage uses whole blood as its denominator, while the second uses plasma. Multiplication correctly passes from the nested plasma fraction to the original whole-blood total.
14. An anticoagulated blood sample separates into a straw-coloured upper fraction and a lower fraction containing cells and cell fragments. The upper fraction occupies nearly \(55\%\) of the sample. The strongest inference is that the upper fraction:
ⓐ. is serum from which all plasma proteins have been removed
ⓑ. contains only water, while all dissolved solutes remain below
ⓒ. consists of formed elements that have lost their pigments
ⓓ. is plasma containing water, proteins and transported solutes
Correct Answer: is plasma containing water, proteins and transported solutes
Explanation: The decisive observations are the straw-coloured fluid appearance, the approximate \(55\%\) share and the separation from cells and cell fragments. Together they identify plasma, the fluid matrix of blood. Anticoagulation prevents clot formation, so clotting factors remain in this upper fluid; it is not serum. Plasma is also not pure water. Water forms most of it, but proteins and other dissolved substances remain present. The lower fraction contains formed elements rather than all solutes. This experiment distinguishes a physical blood fraction from its internal composition: separating cells leaves a complex fluid matrix that still carries proteins, ions, nutrients and other substances in transit. The anticoagulated condition matters: clotting would consume or remove clotting factors and could produce serum instead. The observation supports both the identity and the retained composition of the upper layer. The \(55\%\) value refers to plasma as a fraction of whole blood, not to the water fraction inside plasma or to the formed-element layer.
15. Match each plasma protein with its principal role. A Column II entry is used once.
| Column I | Column II |
|---|
| P. Fibrinogen | 1. Defence mechanisms |
| Q. Globulins | 2. Osmotic balance |
| R. Albumins | 3. Blood coagulation |
ⓐ. P-1, Q-3, R-2
ⓑ. P-3, Q-1, R-2
ⓒ. P-2, Q-1, R-3
ⓓ. P-3, Q-2, R-1
Correct Answer: P-3, Q-1, R-2
Explanation: Fibrinogen is the soluble plasma protein that supplies the precursor for fibrin formation during coagulation, so it maps to blood clotting. Globulins are primarily associated with defence mechanisms in the treatment. Albumins contribute importantly to maintaining osmotic balance in the blood. The mapping is based on distinct physiological roles rather than on the fact that all three occur in plasma. A useful way to separate them is to connect each protein with the process most directly disturbed when it is reduced: fibrin formation, defence-related activity or osmotic regulation. That structure fixes the unique relation P-3, Q-1 and R-2. Remembering only that all three are plasma proteins is insufficient; the functional distinction among them is what makes the mapping biologically meaningful.
16. Assertion: Fibrinogen is a soluble plasma protein that participates in blood coagulation.
Reason: Fibrinogen is the plasma protein primarily responsible for defence mechanisms.
ⓐ. Assertion and Reason are true, and Reason correctly explains Assertion
ⓑ. Assertion and Reason are true, but Reason does not correctly explain Assertion
ⓒ. Assertion is true and Reason is false, so Reason cannot explain Assertion
ⓓ. Assertion is false and Reason is true, so Reason cannot explain Assertion
Correct Answer: Assertion is true and Reason is false, so Reason cannot explain Assertion
Explanation: The assertion is true. Fibrinogen circulates in plasma as a soluble precursor and is converted into fibrin during the clotting process. Fibrin then forms the network that helps produce a clot. The reason is false; the principal defence association among the listed plasma proteins belongs to globulins, not fibrinogen. This distinction prevents two protein functions from being exchanged merely because both proteins occur in the same fluid matrix. The reason neither states a correct function of fibrinogen nor explains its coagulation role. Separating location from function is decisive: sharing a plasma location does not make different proteins physiologically interchangeable. The coagulation role specifically requires the fibrin-forming precursor, whereas a defence association points to globulins.
17. A plasma protein fraction is selectively reduced. Coagulation and osmotic balance remain close to normal, but defence-related activity is most directly affected. The reduced protein family is:
ⓐ. globulins
ⓑ. fibrinogen
ⓒ. albumins
ⓓ. plasma water
Correct Answer: globulins
Explanation: The stated condition preserves two functions while changing a third. Near-normal coagulation indicates that the fibrinogen-related role is not the principal defect. Preserved osmotic balance similarly argues against albumins as the selectively reduced fraction. The remaining plasma-protein function is defence, which is primarily associated with globulins. Water is the major plasma component, but it is not the protein family requested. This is an elimination through linked functions rather than isolated name recall: each plasma protein has a characteristic role, and the unaffected processes provide negative evidence. The pattern of normal clotting, normal osmotic regulation and impaired defence identifies a reduction in globulins. The unchanged functions act as controls within the reasoning, narrowing the missing component to the protein family linked with defence.
18. If the albumin concentration in plasma falls markedly while other plasma components remain unchanged, the most direct prediction is:
ⓐ. weakened plasma defence due to reduced globulin activity
ⓑ. impaired coagulation due to reduced fibrinogen availability
ⓒ. altered ionic balance due to loss of dissolved electrolytes
ⓓ. disturbed osmotic balance due to reduced albumin level
Correct Answer: disturbed osmotic balance due to reduced albumin level
Explanation: Albumins contribute importantly to the osmotic balance of plasma. A marked reduction in albumins would weaken that contribution even when fibrinogen, globulins, water and other solutes remain unchanged. The prediction is limited to the function directly assigned to albumins at this level. Defence mechanisms are primarily associated with globulins, while fibrinogen participates in coagulation. Lower albumin does not transform one plasma protein into another or remove all ions. The changed-condition reasoning links a selective component loss to its specific physiological role: altering the protein that supports osmotic balance should disturb regulation of water distribution between the blood and surrounding tissues. The prediction remains specific and does not imply that every other plasma function disappears. Plasma composition must be interpreted at the correct level: plasma is a fraction of whole blood, whereas water, proteins and solutes are proportions within the plasma fraction.
19. A plasma preparation retains normal fibrin-forming capacity but shows both reduced defence-related protein activity and disturbed osmotic balance. The missing protein combination is most likely:
ⓐ. fibrinogen and globulins
ⓑ. fibrinogen and albumins
ⓒ. globulins and albumins
ⓓ. fibrinogen alone
Correct Answer: globulins and albumins
Explanation: Normal fibrin-forming capacity indicates that fibrinogen is still available, so combinations containing missing fibrinogen do not fit the evidence. The two altered functions point to two other plasma proteins. Globulins are primarily associated with defence, while albumins contribute to osmotic balance. Their combined absence accounts for both observations without disrupting the retained clotting precursor. Preserved clotting narrows the possibilities first, and the paired functional losses then identify the missing components. This demonstrates how several plasma proteins can share one fluid compartment while remaining distinguishable through their specific physiological contributions. The preserved fibrin formation is a decisive qualifier: it rules out any proposed loss that includes fibrinogen. The paired functional deficits can then be assigned independently and specifically to globulins and albumins.
20. Consider the following statements about substances carried in plasma.
I. Ions such as \(\mathrm{Na^+}\), \(\mathrm{Ca^{2+}}\), \(\mathrm{Mg^{2+}}\), \(\mathrm{HCO_3^-}\) and \(\mathrm{Cl^-}\) occur in plasma.
II. Glucose, amino acids and lipids may be present as substances in transit.
III. Every substance transported by plasma is a formed element.
IV. Plasma carries materials in addition to water and proteins.
ⓐ. I and III only
ⓑ. I, II and IV only
ⓒ. II and III only
ⓓ. I, II, III and IV
Correct Answer: I, II and IV only
Explanation: Plasma is a complex transport medium rather than water containing only suspended cells. It includes inorganic ions such as sodium, calcium, magnesium, bicarbonate and chloride, together with organic substances such as glucose, amino acids and lipids moving between sites of absorption, storage, use or removal. These dissolved or dispersed substances are not formed elements. Formed elements are erythrocytes, leucocytes and platelets, which are suspended in plasma as a separate component class. The fourth statement captures the broader composition of plasma, while the third incorrectly merges transported solutes with cellular components. The valid set recognises both the listed solutes and the distinction between plasma contents and formed elements. This distinction is essential when interpreting blood composition, since transported cargo and suspended cellular components occupy the same sample but belong to different categories.
