Plant Water and Human Health Practice Quiz (25 questions)

1. What feature of root hair cells makes them effective at absorbing water and mineral ions from soil?

A. Their thick outer walls prevent dissolved substances from entering.

B. Their long extensions provide a large surface area for absorption.

C. Their hollow interiors provide a continuous pathway to the leaves.

D. Their position inside the root connects them directly to the xylem.

Answer: (B)

Explanation

Root hair cells extend over the root surface, giving them a large area for absorbing water and mineral ions. A direct connection to xylem describes transport through the root, not the surface-area adaptation of root hairs.

2. Which route does water and dissolved mineral ions take as they enter a root hair cell from soil?

A. They enter through the cell wall and then move along the outside of the membrane.

B. They pass from spaces between soil particles through the cell wall and membrane into the cytoplasm.

C. They travel from the soil spaces directly into the xylem without crossing a cell membrane.

D. They move from the cytoplasm through the membrane and cell wall into spaces between soil particles.

Answer: (B)

Explanation

Water and dissolved mineral ions move from soil spaces through the root hair cell wall and membrane into the cytoplasm. Entering the xylem without crossing a membrane skips the stated route into the root hair cell.

3. What structural feature makes a xylem vessel a hollow tube?

A. It is formed from dead cells whose contents remain inside, with intact end walls.

B. It is formed from dead cells whose contents and end walls have disappeared.

C. It is formed from living cells that lack cell walls but retain their contents.

D. It is formed from living cells whose contents remain, separated by perforated end walls.

Answer: (B)

Explanation

Xylem vessels are formed from dead cells after their contents and end walls disappear, leaving cell walls around an empty space. Living cells with contents and perforated end walls do not match this description of a xylem vessel.

4. In a coloured-water stalk investigation, what do blue spots in a cross-section indicate?

A. They indicate xylem cells stained by the coloured water.

B. They indicate spaces between cells through which the dye passed.

C. They indicate root hair cells that absorbed water from the soil.

D. They indicate the outer surface cells that first touched the dye.

Answer: (A)

Explanation

Blue spots in the cross-section indicate xylem cells reached by the coloured water. Root hair cells absorb water from soil, but they are not what blue spots in the stalk cross-section identify.

5. Which procedure can trace the upward movement of water through a stalk?

A. Place its clean cut end in plain water, observe the water move upward, then cut along the stalk to find unstained xylem.

B. Place its intact side in coloured water, observe the dye move downward, then remove the outer surface to find stained cells.

C. Place its cut end in coloured water, observe the dye remain near the base, then cut across the stalk to find unstained cells.

D. Place its clean cut end in coloured water, observe the dye move upward, then cut across the stalk to find stained xylem.

Answer: (D)

Explanation

The procedure uses a clean cut end in coloured water, observation of upward dye movement, and a cross-section to locate stained xylem. Plain water would not provide dye to trace, and cutting along the stalk does not follow the described method.

6. What does transpiration describe in a plant?

A. The movement of dissolved minerals through stems

B. The loss of water vapour from leaves

C. The conversion of liquid water into vapour

D. The uptake of liquid water by roots

Answer: (B)

Explanation

Transpiration is water vapour lost from leaves. Evaporation, a closely related process, describes liquid water changing into water vapour.

7. Which sequence describes how water leaves a leaf during transpiration?

A. Water moves from stomata into air spaces, condenses on cell walls, then enters the xylem

B. Water evaporates from xylem into the leaf, then diffuses through cell walls into stomata

C. Water moves from leaf cells into xylem, then evaporates through the roots into the air

D. Water moves from xylem into leaf cells, evaporates from cell walls into air spaces, then diffuses through stomata

Answer: (D)

Explanation

Water passes from the xylem into leaf cells, evaporates from their walls into air spaces, and diffuses out through stomata. The alternative sequence beginning with water entering through stomata reverses the direction of transpiration.

8. How does water help support a plant?

A. It fills vacuoles so cells become firm and press against one another

B. It carries sugars into roots so they anchor the plant more firmly

C. It fills air spaces so leaves remain upright through increased buoyancy

D. It thickens cell walls so they remain rigid without cell pressure

Answer: (A)

Explanation

Water in vacuoles makes cells firm, and pressure between these firm cells supports the plant. Cell walls provide structure, but the described support comes from water-filled cells pressing against one another.

9. A plant collapses after losing water, and its cells feel soft and floppy. What condition is the plant in?

A. It is wilted because its cells lack enough water

B. It is supported because its cells are pressing firmly together

C. It is photosynthesizing because its cells are producing glucose

D. It is transpiring because its cells are losing dissolved minerals

Answer: (A)

Explanation

A plant is wilted when its cells lack enough water, become soft and floppy, and the plant collapses. Firm cells pressing together describe support in a well-watered plant, not wilting.

10. How does water help move mineral salts around a plant?

A. It stores mineral salts in leaf vacuoles and releases them into the soil

B. It transports dissolved mineral salts through the xylem from roots to other parts

C. It carries mineral salts through stomata from the air into the roots

D. It converts mineral salts into sugars in the leaves before they enter the phloem

Answer: (B)

Explanation

Water transports dissolved mineral salts through the xylem from the roots to other parts of the plant. The phloem is not the route specified for this transport.

11. What role does water play in photosynthesis?

A. It cools leaf cells while carbon dioxide is converted into mineral salts

B. It carries glucose from the leaves to the roots through the xylem

C. It is a reactant used with carbon dioxide to produce glucose and oxygen

D. It is a product formed when glucose combines with oxygen

Answer: (C)

Explanation

Water is a reactant in photosynthesis, which uses water and carbon dioxide to make glucose and oxygen. Cooling leaves is a separate effect of water evaporation, not water’s role as a photosynthetic reactant.

12. Which description best defines excretion?

A. Removing undigested food that has travelled through the digestive system

B. Removing wastes made in cells or substances present in excess that have been inside the body

C. Breaking food into small molecules that can pass into the bloodstream

D. Taking useful substances from the blood into cells for growth

Answer: (B)

Explanation

Excretion removes substances made in cells as wastes or substances present in excess that have been inside the body. Undigested food leaving the digestive system is not excretory waste because it has not been part of the body.

13. Why are faeces not classified as excretory waste?

A. The food in them travelled through the digestive system without becoming part of the body

B. They contain excess water that was removed from the blood by the kidneys

C. They consist of urea produced by liver cells during protein processing

D. They contain carbon dioxide produced inside cells during respiration

Answer: (A)

Explanation

Faeces are not excretory waste because the food within them has not been part of the body. Urea and carbon dioxide, by contrast, are examples of substances made inside the body and excreted.

14. Which set contains substances that humans excrete?

A. Carbon dioxide from respiration, urea made in liver cells, and excess water

B. Oxygen from photosynthesis, glucose made in liver cells, and mineral salts

C. Faeces from digestion, carbon dioxide from respiration, and absorbed glucose

D. Digested protein, oxygen from respiration, and water used in photosynthesis

Answer: (A)

Explanation

Humans excrete carbon dioxide made during respiration, urea made in liver cells, and excess water. Faeces are not included because the food in them has not been part of the body.

15. What is urine formed from when the kidneys remove waste from the blood?

A. Excess water containing dissolved nutrients returned to the blood

B. Urea dissolved in excess water removed from the blood

C. Blood cells and urea combined inside the ureters

D. Urea produced by the bladder and mixed with filtered blood

Answer: (B)

Explanation

Urine is the solution formed when urea dissolves in excess water removed from the blood by the kidneys. Urea is the waste substance, not the name for the whole solution.

16. What role do the kidneys play in urine formation?

A. They carry urine from the bladder back into the bloodstream

B. They filter blood, remove urea and excess water, and form urine

C. They add urea to blood after excess water has been removed

D. They store urine until it leaves the body through the urethra

Answer: (B)

Explanation

The kidneys filter blood and remove urea and excess water to form urine. The bladder stores urine; it does not perform the kidneys’ filtering function.

17. Which route does urine take from the kidneys before leaving the body?

A. The ureters carry it out of the body, bypassing the bladder

B. Ureters carry it to the bladder, and the urethra carries it out

C. The urethra carries it to the bladder, and the ureters carry it out

D. The bladder carries it to the kidneys, and the ureters carry it out

Answer: (B)

Explanation

Urine travels from each kidney through a ureter to the bladder, then leaves the body through the urethra. The urethra does not carry urine from the kidneys to the bladder.

18. Which description correctly identifies a fetus?

A. A baby who has been born and is still dependent on its mother

B. An unfertilized egg cell developing inside the mother

C. A newborn developing outside the mother before birth

D. A baby developing inside its mother before birth

Answer: (D)

Explanation

A fetus is a baby developing inside its mother before birth. A baby who has already been born is no longer a fetus.

19. How does a fetus obtain needed substances and dispose of substances it excretes?

A. It produces needed substances itself and transfers waste to the mother’s lungs

B. It receives needed substances from the mother but disposes of waste independently

C. It depends on its mother to supply needed substances and remove excreted ones

D. It obtains needed substances from swallowed food and excretes them into the amniotic fluid

Answer: (C)

Explanation

The fetus depends on its mother both for needed substances and for removal of substances it excretes. The fetus does not handle waste disposal independently.

20. How do substances pass between maternal and fetal blood systems?

A. The blood remains separate, while substances diffuse between the systems

B. The maternal blood enters the fetus, while fetal excretions remain in its blood

C. The blood mixes directly, allowing substances to circulate as one supply

D. The fetal blood enters the mother, while maternal substances cannot pass across

Answer: (A)

Explanation

The mother’s and fetus’s blood do not mix, but substances diffuse between their blood systems, with fetal excretory substances diffusing in the opposite direction. Direct mixing of the two blood supplies is the key misconception.

21. A developing fetus needs support for bone growth, while its mother also needs to maintain her bones and teeth; which nutrient serves these roles?

A. Iron

B. Calcium

C. Protein

D. Carbohydrate

Answer: (B)

Explanation

Calcium supports fetal bone growth and helps maintain the mother’s bones and teeth. Iron is needed to make haemoglobin, rather than serving these bone and tooth roles.

22. Which substances from a pregnant woman’s blood can diffuse into the fetus’s blood when she smokes?

A. Carbon monoxide and calcium

B. Carbon dioxide and alcohol

C. Nicotine and iron

D. Carbon monoxide and nicotine

Answer: (D)

Explanation

Carbon monoxide and nicotine from the pregnant woman’s blood diffuse into the fetus’s blood. Iron and calcium are nutrients, not the pair identified as smoking-related substances that diffuse to the fetus.

23. How can carbon monoxide in a pregnant woman’s blood affect fetal development?

A. It damages fetal blood vessels, reducing blood flow while leaving oxygen transport unchanged

B. It blocks nutrient diffusion to the fetus, limiting cell growth without affecting respiration

C. It reduces oxygen transport by haemoglobin, limiting fetal cell respiration and energy release

D. It increases oxygen transport by haemoglobin, causing fetal cells to release excess energy

Answer: (C)

Explanation

Carbon monoxide reduces the amount of oxygen haemoglobin can transport, so fetal cells receive less oxygen, respire less, and release less energy, which may affect their development. Damage to blood vessels is associated with nicotine, not the carbon monoxide mechanism described here.

24. Why can a drug taken by a pregnant woman harm the fetus?

A. Most drugs remain in maternal blood, but needed drugs can harm the fetus

B. Drugs enter fetal blood only when prescribed, and prescribed drugs cause harm

C. Drugs pass from fetal blood into maternal blood, where they can disrupt development

D. Most drugs enter fetal blood, and a drug the fetus does not need can cause harm

Answer: (D)

Explanation

Most drugs taken by a pregnant woman enter the fetus’s blood, and drugs the fetus does not need can be harmful. A prescribed drug may be needed for the mother’s health, so prescription status alone does not mean it is harmful.

25. A pregnant woman is considering an over-the-counter medicine and regularly drinks cola; which guidance best follows the recommended precautions?

A. Stop any prescribed medicine and drink cola freely if it contains no alcohol

B. Check before taking the medicine and avoid drinking a lot of cola

C. Take the medicine without checking and replace cola with a large amount of coffee

D. Check only after taking the medicine and avoid water instead of cola

Answer: (B)

Explanation

Pregnant women should check before taking non-prescription drugs and avoid drinking a lot of coffee or cola because caffeine may harm a developing fetus. Avoiding water is not part of the guidance, and it does not replace checking medicines.