1) What is the primary function of red blood cells (RBC) in the human body?
a) To transport nutrients
b) To fight against germs
c) To carry oxygen to body cells
d) To form blood clots
Answer: c) To carry oxygen to body cells
Explanation: Red blood cells contain hemoglobin, a red pigment that binds with oxygen and transports it to all parts of the body.
2) Which part of the human circulatory system is responsible for carrying oxygen-rich blood from the heart to all parts of the body?
a) Veins
b) Capillaries
c) Arteries
d) Platelets
Answer: c) Arteries
Explanation: Arteries carry oxygen-rich blood from the heart to all parts of the body. They have thick elastic walls to handle high pressure.
3) What is the role of platelets in the blood?
a) Transporting oxygen
b) Filtering waste
c) Forming blood clots
d) Carrying nutrients
Answer: c) Forming blood clots
Explanation: Platelets are essential for blood clotting, which helps in stopping bleeding from wounds.
4) Which statement is true about the human heart?
a) It has two chambers.
b) It pumps only oxygen-rich blood.
c) It is located on the right side of the chest.
d) It has four chambers to prevent oxygen-rich and carbon dioxide-rich blood from mixing.
Answer: d) It has four chambers to prevent oxygen-rich and carbon dioxide-rich blood from mixing.
Explanation: The human heart has four chambers – two atria and two ventricles, which prevent the mixing of oxygenated and deoxygenated blood.
5) What is the main excretory product in human beings?
a) Carbon dioxide
b) Uric acid
c) Urea
d) Ammonia
Answer: c) Urea
Explanation: Urea is the primary waste product in human urine, formed in the liver from ammonia.
6) Which of the following is a part of the human excretory system?
a) Esophagus
b) Kidney
c) Lungs
d) Small intestine
Answer: b) Kidney
Explanation: Kidneys are a crucial part of the excretory system, filtering blood and producing urine.
7) In plants, which tissue is responsible for the transport of water and minerals from the roots to the leaves?
a) Phloem
b) Epidermis
c) Xylem
d) Cortex
Answer: c) Xylem
Explanation: Xylem is the vascular tissue in plants responsible for the transport of water and nutrients from the roots to other parts of the plant.
8) What process in plants involves the loss of water vapor through the stomata in leaves?
a) Photosynthesis
b) Transpiration
c) Respiration
d) Absorption
Answer: b) Transpiration
Explanation: Transpiration is the process by which water evaporates from the leaves of plants, aiding in water and nutrient transport and cooling the plant.
9) Which component of blood is responsible for fighting infections?
a) Red blood cells (RBC)
b) White blood cells (WBC)
c) Platelets
d) Plasma
Answer: b) White blood cells (WBC)
Explanation: White blood cells play a crucial role in the immune system, helping to fight infections and foreign bodies.
10) What is the main function of the human heart in the circulatory system?
a) To filter blood
b) To produce blood cells
c) To pump blood throughout the body
d) To absorb nutrients
Answer: c) To pump blood throughout the body
Explanation: The heart acts as a pump, continuously circulating blood throughout the body, delivering oxygen and nutrients, and removing waste products.
11) What is the primary waste product removed through sweating in humans?
a) Ammonia
b) Carbon dioxide
c) Uric acid
d) Salts and urea
Answer: d) Salts and urea
Explanation: Sweat primarily consists of water, salts, and urea, and it helps in thermoregulation and excretion.
12) In plants, which vascular tissue is responsible for the transport of food from the leaves to other parts of the plant?
a) Xylem
b) Phloem
c) Cortex
d) Epidermis
Answer: b) Phloem
Explanation: Phloem is responsible for the transport of sugars and other nutrients produced by the leaves to different parts of the plant.
13) Which of the following is not a function of stomata in plants?
a) Gas exchange
b) Transpiration
c) Transport of nutrients
d) Regulation of water loss
Answer: c) Transport of nutrients
Explanation: Stomata are primarily involved in gas exchange and transpiration, not in the direct transport of nutrients.
14) Why do arteries have thick walls?
a) To filter blood
b) To transport oxygen-rich blood at high pressure
c) To store blood
d) To produce blood cells
Answer: b) To transport oxygen-rich blood at high pressure
Explanation: Arteries have thick, elastic walls to withstand and maintain the high pressure at which oxygen-rich blood is pumped from the heart.
15) How does transpiration benefit plants?
a) It aids in photosynthesis
b) It helps in distributing nutrients
c) It creates a cooling effect and helps in water and nutrient transport
d) It attracts pollinators
Answer: c) It creates a cooling effect and helps in water and nutrient transport
Explanation: Transpiration helps in cooling the plant and creates a suction force that aids in the ascent of sap (water and nutrients) from the roots to the leaves.
16) Which of the following statements about the human excretory system is true?
a) The kidneys filter nutrients from the blood
b) The bladder produces urine
c) The urethra carries urine from the kidneys to the bladder
d) The kidneys filter waste from the blood, which is then excreted as urine
Answer: d) The kidneys filter waste from the blood, which is then excreted as urine
Explanation: The kidneys play a crucial role in filtering waste products from the blood, which are then excreted from the body as urine through the urinary system.
17) What is the main function of root hairs in plants?
a) To anchor the plant in soil
b) To absorb water and minerals from the soil
c) To store food
d) To perform photosynthesis
Answer: b) To absorb water and minerals from the soil
Explanation: Root hairs increase the surface area of the root for absorbing water and mineral nutrients from the soil.
18) What is the typical pulse rate of a resting adult human?
a) 30-40 beats per minute
b) 50-60 beats per minute
c) 72-80 beats per minute
d) 90-100 beats per minute
Answer: c) 72-80 beats per minute
Explanation: In a resting adult, the typical pulse rate is between 72 and 80 beats per minute.
19) Which type of blood vessel carries carbon dioxide-rich blood back to the heart?
a) Arteries
b) Veins
c) Capillaries
d) Aorta
Answer: b) Veins
Explanation: Veins carry carbon dioxide-rich blood from all parts of the body back to the heart.
20) In which organ of the human body is urea formed?
a) Liver
b) Kidney
c) Heart
d) Stomach
Answer: a) Liver
Explanation: Urea is formed in the liver from ammonia, a waste product of protein metabolism.
21) Why do plants release water through transpiration?
a) To absorb more nutrients
b) To release oxygen
c) To maintain temperature and facilitate nutrient transport
d) To attract insects for pollination
Answer: c) To maintain temperature and facilitate nutrient transport
Explanation: Transpiration helps in cooling the plant and creates a pull that aids in the transport of water and nutrients from the roots to the leaves.
22) Which component in blood helps in clotting at the site of an injury?
a) Red blood cells
b) White blood cells
c) Platelets
d) Plasma
Answer: c) Platelets
Explanation: Platelets are crucial for blood clotting, which prevents excessive bleeding when injuries occur.
23) What happens to the pulse rate after physical exercise?
a) Decreases significantly
b) Remains the same
c) Increases temporarily
d) Cannot be determined
Answer: c) Increases temporarily
Explanation: After physical exercise, the pulse rate increases temporarily to meet the higher oxygen demand of the body.
24) Which process in plants is responsible for the upward movement of water from roots to leaves?
a) Photosynthesis
b) Transpiration pull
c) Respiration
d) Capillary action
Answer: b) Transpiration pull
Explanation: Transpiration pull is the primary mechanism driving the upward movement of water and nutrients from the roots to the leaves in plants.
25) What is the function of haemoglobin in the blood?
a) To fight infections
b) To clot blood
c) To carry oxygen
d) To filter waste
Answer: c) To carry oxygen
Explanation: Haemoglobin in red blood cells binds with oxygen and transports it to different parts of the body.
26) Which organ in the human body is primarily involved in filtering blood and forming urine?
a) Heart
b) Liver
c) Kidney
d) Lung
Answer: c) Kidney
Explanation: Kidneys filter waste products from the blood and are involved in the production of urine.
27) In plants, how does water mainly enter the root hairs?
a) Through transpiration
b) By photosynthesis
c) Via osmosis
d) Through active transport
Answer: c) Via osmosis
Explanation: Water enters the root hairs mainly through osmosis, a process where water moves from a region of lower solute concentration to a region of higher solute concentration.
28) What is the role of the xylem in plants?
a) To transport food
b) To carry water and minerals
c) To facilitate gas exchange
d) To store energy
Answer: b) To carry water and minerals
Explanation: Xylem is responsible for transporting water and minerals from the roots to other parts of the plant.
29) What happens to the human heart rate during physical exercise?
a) Increases
b) Decreases
c) Remains constant
d) Fluctuates unpredictably
Answer: a) Increases
Explanation: During physical exercise, the heart rate increases to supply more oxygen and nutrients to the muscles.
30) Which part of the human excretory system stores urine before it is excreted?
a) Kidney
b) Ureter
c) Bladder
d) Urethra
Answer: c) Bladder
Explanation: The urinary bladder stores urine until it is ready to be excreted from the body.
31) Why are sweat glands an important part of the human excretory system?
a) They regulate body temperature
b) They excrete excess water and salts
c) They absorb nutrients
d) Both a) and b)
Answer: d) Both a) and b)
Explanation: Sweat glands help in thermoregulation by releasing sweat (which cools the body when it evaporates) and also excrete excess water and salts.
32) What is the primary reason for the red color of human blood?
a) Presence of plasma
b) High water content
c) Red blood cells containing haemoglobin
d) Presence of white blood cells
Answer: c) Red blood cells containing haemoglobin
Explanation: The red color of blood is due to haemoglobin in the red blood cells, which binds with oxygen giving blood its red color.