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Q1. The primary function of red blood cells is to:
Red blood cells contain hemoglobin, a protein that binds to oxygen in the lungs and transports it to all body tissues. White blood cells fight infection, platelets clot blood, and antibodies are produced by white blood cells. Transporting oxygen is the main job of red blood cells.
Q2. The blood vessels that carry blood away from the heart are called:
Arteries are blood vessels that carry blood away from the heart to various parts of the body. They usually carry oxygenated blood (except the pulmonary artery). Veins carry blood toward the heart, capillaries connect arteries and veins, and platelets are blood components.
Q3. Which component of blood helps in clotting?
Platelets are small cell fragments in the blood that help in clotting. When a blood vessel is injured, platelets gather at the site and release chemicals that start the clotting process. Red blood cells carry oxygen, white blood cells fight infection, and plasma is the liquid part of blood.
Q4. In plants, water and minerals are transported through:
Xylem is the plant tissue responsible for transporting water and dissolved minerals from the roots to the rest of the plant. Phloem transports food, cambium is a growth tissue, and cortex is the outer layer of roots and stems.
Q5. The food prepared by leaves is transported to other parts of the plant through:
Phloem transports the food (sugars) produced by leaves during photosynthesis to all other parts of the plant, including roots, stems, and fruits. Xylem transports water and minerals, stomata are pores for gas exchange, and root hairs absorb water.
Q6. Which of the following organisms does not have a circulatory system?
Amoeba is a unicellular organism that does not have a circulatory system. It relies on diffusion for the exchange of gases and waste products. Earthworms, fish, and frogs have well-developed circulatory systems because they are multicellular organisms.
Q7. The process of loss of water in the form of water vapor from plant leaves is called:
Transpiration is the loss of water vapor from plant leaves through stomata. It helps in cooling the plant and creating suction for water absorption. Evaporation is a general process, condensation is gas to liquid, and osmosis is water movement across a membrane.
Q8. Which chamber of the human heart pumps blood to the lungs?
The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery. The right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the left ventricle pumps oxygenated blood to the body.
Q9. The movement of molecules from a region of higher concentration to a region of lower concentration without using energy is called:
Diffusion is the passive movement of molecules from a region of higher concentration to lower concentration until equilibrium is reached. It does not require energy. Osmosis is the diffusion of water, and active transport requires energy.
Q10. Root hairs absorb water from the soil mainly by the process of:
Root hairs absorb water from the soil by osmosis. The concentration of solutes inside the root hair cells is higher than in the soil water, so water moves into the root hairs across the semipermeable membrane. Diffusion and active transport are also involved but osmosis is the main process for water absorption.
Q11. Which of the following statements about diffusion in unicellular organisms is correct?
In unicellular organisms like Amoeba and Paramecium, diffusion is sufficient for the exchange of gases (oxygen and carbon dioxide) and removal of waste products because of their small size and large surface area-to-volume ratio. They do not need complex organs like a heart or blood vessels.
Q12. The wall of which blood vessel is the thinnest?
Capillaries have the thinnest walls, consisting of just a single layer of cells (endothelium). This thinness allows for efficient exchange of gases, nutrients, and waste products between blood and tissues. Arteries and veins have thicker walls with more layers.
Q13. The upward movement of water and minerals in xylem is mainly due to:
The upward movement of water in xylem is mainly driven by transpiration pull. Water evaporates from leaves, creating a negative pressure that pulls water upward from the roots. Root pressure also helps but is not the main force. Gravity works against upward movement, and phloem transports food.
Q14. Which blood vessel carries oxygenated blood from the lungs to the heart?
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. The pulmonary artery carries deoxygenated blood from the heart to the lungs. The aorta carries oxygenated blood from the heart to the body, and the vena cava carries deoxygenated blood from the body to the heart.
Q15. In higher plants, xylem and phloem together are called:
Xylem and phloem together form the vascular tissues of plants. They are responsible for the transport of water, minerals, and food. Epidermis is the outer protective layer, ground tissues are for storage and support, and meristematic tissues are for growth.
Q16. Which of the following is not a function of transpiration?
Transpiration helps cool the plant, creates suction for water and mineral absorption, and helps in the transport of minerals. However, providing carbon dioxide for photosynthesis is the function of stomata opening for gas exchange, not transpiration itself. Transpiration is the loss of water vapor.
Q17. The liquid part of blood that carries dissolved food, hormones, and waste products is:
Plasma is the liquid part of blood that carries dissolved food, hormones, waste products, and blood cells. Cytoplasm is inside cells, lymph is a fluid in the lymphatic system, and serum is plasma without clotting factors.
Q18. Which type of simple multicellular plant would mostly rely on diffusion for transport?
Simple multicellular plants like Spirogyra (filamentous algae) rely mostly on diffusion for transport because they are thin and have a large surface area-to-volume ratio. Tall trees, rose bushes, and wheat plants need specialized vascular tissues (xylem and phloem) for transport.
Q19. The rhythmic contraction and relaxation of the heart is called:
The rhythmic contraction and relaxation of the heart is called a heartbeat. Pulse is the throbbing of arteries, circulation is the movement of blood, and systole is the contraction phase of the heart. The heartbeat is the complete cycle of contraction and relaxation.
Q20. The tiny pores present on leaf surfaces through which transpiration occurs are called:
Stomata are tiny pores on leaf surfaces through which transpiration (water vapor loss) and gas exchange (CO₂ and O₂) occur. Lenticels are pores on stems, the cuticle is the waxy outer layer, and hydathodes release water in liquid form (guttation).
Q21. Which of the following correctly shows the path of blood in a double circulation system?
In double circulation, blood passes through the heart twice. The path is: Heart → lungs (pulmonary circulation) → Heart → body (systemic circulation) → Heart. This ensures oxygenated blood is separated from deoxygenated blood.
Q22. The conducting cells of xylem that are dead at maturity and have thick lignified walls are called:
Tracheids and vessels are the conducting cells of xylem. They are dead at maturity and have thick lignified walls that make them strong and waterproof. Sieve tubes and companion cells are part of phloem, and phloem fibers provide support.
Q23. Which of the following is an example of active transport in plants?
Absorption of mineral ions by root hairs is an example of active transport because it requires energy to move ions against a concentration gradient. Water movement in xylem is passive, transpiration is physical loss, and diffusion is passive.
Q24. In which direction does phloem transport food?
Phloem transports food (sugars) in both upward and downward directions depending on the plant’s needs. It moves from sources (where food is produced or stored) to sinks (where food is needed). This is called translocation. Xylem only moves water and minerals upward.
Q25. The valve present between the right atrium and right ventricle is called:
The tricuspid valve is located between the right atrium and the right ventricle. It prevents backflow of blood into the right atrium when the right ventricle contracts. The bicuspid valve is on the left side, semilunar valves are at the exits of ventricles, and the aortic valve is the semilunar valve at the aorta.
Q26. Which of the following plants would have the highest rate of transpiration?
Transpiration is highest in hot, windy, and dry conditions because water evaporates faster. A sunflower on a hot, windy day would lose water rapidly. Cacti and pine trees have adaptations to reduce transpiration, and water lilies are in a humid environment.
Q27. The main waste product transported by blood from body cells to excretory organs is:
Blood transports carbon dioxide (from cellular respiration) and urea (from protein breakdown) from body cells to excretory organs (lungs for CO₂, kidneys for urea). Oxygen is transported from lungs to cells, not as a waste product.
Q28. In higher plants, the movement of food through phloem occurs by:
The movement of food through phloem is explained by the pressure flow hypothesis (also called the source-sink theory). Food is loaded into phloem at sources (like leaves), creating high pressure, and unloaded at sinks, causing flow. Transpiration pull and root pressure are for xylem transport.
Q29. Which of the following unicellular organisms uses cilia to create water currents for bringing in food and oxygen?
Paramecium uses tiny hair-like structures called cilia to create water currents that bring in food and oxygen. Amoeba uses pseudopodia, Euglena uses a flagellum, and bacteria use various structures but not cilia for feeding in this way.
Q30. The pigment present in red blood cells that binds with oxygen is:
Hemoglobin is the red pigment in red blood cells that binds with oxygen to transport it from the lungs to tissues. Hemocyanin is found in some invertebrates, chlorophyll is for photosynthesis, and myoglobin stores oxygen in muscles.
Q31. Which statement about veins is correct?
Veins have valves that prevent the backflow of blood, especially in the limbs where blood flows against gravity. They do not always carry deoxygenated blood (pulmonary veins carry oxygenated blood). They have thinner walls than arteries and carry blood toward the heart.
Q32. The loss of water from plants in the form of liquid droplets is called:
Guttation is the loss of water in liquid form from plant leaves through hydathodes (special pores) when root pressure is high and transpiration is low. Transpiration is loss of water vapor, bleeding is loss of sap from wounds, and evaporation is a general term.
Q33. Which of the following is not transported by blood?
Blood transports oxygen, carbon dioxide, food (nutrients), hormones, and waste products. Sunlight is not transported by blood; it is absorbed by plants for photosynthesis or by skin for vitamin D synthesis. Blood does not carry sunlight.
Q34. The tissue responsible for the transport of water and minerals from roots to leaves in a hibiscus plant is:
Xylem transports water and minerals from roots to leaves in all vascular plants, including hibiscus. Phloem transports food, cambium is a growth tissue, and cortex is the outer layer of roots and stems. Xylem is the correct vascular tissue for water transport.
Q35. A person has a cut and blood is oozing out slowly. Which component of blood will first act to stop the bleeding?
Platelets are the first to act at the site of a wound. They stick to the damaged area and release chemicals that start the clotting process. Red blood cells carry oxygen, white blood cells fight infection, and plasma proteins have various functions.
Q36. In simple multicellular plants like Spirogyra, how do food and gases move between cells?
In simple multicellular plants like Spirogyra, food and gases move between cells by diffusion through cell walls and cytoplasm. They lack specialized vascular tissues. Diffusion is sufficient for their needs because they are thin and have a large surface area-to-volume ratio.
Q37. The largest artery in the human body is:
The aorta is the largest artery in the human body. It carries oxygenated blood from the left ventricle to the rest of the body. The pulmonary artery carries blood to the lungs, the carotid artery supplies the head, and the femoral artery supplies the leg.
Q38. Which of the following is an adaptation to reduce transpiration in desert plants?
Desert plants have adaptations to reduce transpiration, such as sunken stomata (trapped in pits), thick cuticles (waxy layers), and reduced leaves. These features minimize water loss. Large leaves and numerous stomata would increase transpiration.
Q39. The pressure exerted by the blood against the wall of an artery during ventricular contraction is called:
Systolic pressure is the pressure exerted on artery walls when the ventricles contract (systole). It is the higher number in a blood pressure reading. Diastolic pressure is when the heart relaxes, pulse pressure is the difference between systolic and diastolic, and osmotic pressure is related to solutes.
Q40. In plants, the movement of minerals from soil into root hair cells often requires energy because:
Minerals are often absorbed by active transport because their concentration in the soil is lower than inside the root cells. This means minerals must be pumped against a concentration gradient, which requires energy. Water moves by osmosis, not energy.
Q41. Which of the following statements about diffusion is false?
Diffusion occurs in gases, liquids, and solids, not just liquids. It is the movement of particles from higher to lower concentration and does not require energy. Diffusion is important in unicellular organisms for gas exchange and waste removal. The statement that it occurs only in liquids is false.
Q42. The material that makes xylem walls strong and waterproof is:
Lignin is a complex polymer that makes xylem cell walls thick, strong, and waterproof. It allows xylem to transport water efficiently and provides structural support. Cellulose is the main component of cell walls, pectin is in the middle lamella, and suberin is in cork cells.
Q43. In which of the following would you expect the fastest rate of diffusion?
Diffusion is fastest in small organisms with a large surface area-to-volume ratio and in warm conditions because particles move faster. A single-celled alga in warm water would have rapid diffusion of oxygen. Thick tree trunks, dry seed coats, and potato tubers would have much slower diffusion.
Q44. The function of white blood cells is primarily to:
White blood cells are part of the immune system and primarily function to fight infection by destroying pathogens. Red blood cells carry oxygen, platelets clot blood, and plasma transports nutrients. White blood cells are the body’s defense cells.
Q45. The continuous column of water in xylem does not break easily because of:
The continuous column of water in xylem is maintained by cohesion (water molecules sticking together) and adhesion (water molecules sticking to xylem walls). These properties prevent the water column from breaking under tension. Root pressure and transpiration help, but cohesion and adhesion are the main forces keeping the column intact.
Q46. Which of the following correctly matches the plant tissue with its function?
Xylem transports water and minerals from roots to the rest of the plant. Phloem transports food (sugars) from leaves to other parts. The correct match is xylem with water and minerals. Phloem does not transport water or minerals primarily.
Q47. The two upper chambers of the human heart are called:
The two upper chambers of the human heart are the atria (singular: atrium). They receive blood from the body (right atrium) or from the lungs (left atrium). The lower chambers are the ventricles. The septum is the wall dividing the heart, and valves control blood flow.
Q48. Why is transpiration called a necessary evil?
Transpiration is called a “necessary evil” because it causes water loss (which can be harmful in dry conditions) but also helps in cooling the plant and creating suction for water and mineral absorption. It is essential but has a downside. It does not stop photosynthesis and occurs during the day.
Q49. The movement of water across a semipermeable membrane from dilute solution to concentrated solution is called:
Osmosis is the movement of water across a semipermeable membrane from a region of lower solute concentration (dilute) to higher solute concentration (concentrated). Diffusion is the movement of any molecules, active transport requires energy, and plasmolysis is the shrinking of cells.
Q50. Which of the following sequences correctly represents the path of a drop of blood from the vena cava to the lungs?
The correct path of blood from the vena cava to the lungs is: Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs. The pulmonary artery carries deoxygenated blood to the lungs. The other options have incorrect chambers or vessels.