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12th Class Biology Chapter 15 MCQs with Answers

12th Class Biology Chapter 15 MCQs

Master the concept of homeostasis with our comprehensive 12th Class Biology Chapter 15 MCQs. These practice questions focus on key topics such as temperature regulation, water balance, and cellular equilibrium. Perfectly aligned with your syllabus, these MCQs help sharpen your understanding for exams and improve retention. Boost your preparation with trending keywords like biology MCQs for exams, Homeostasis quiz, and biology chapter tests. Tackle challenging questions and stay ahead!

What is homeostasis?
a) A state of imbalance
b) The body’s ability to maintain stable internal conditions
c) A disease caused by external factors
d) A process that occurs only in plants

Answer
b) The body’s ability to maintain stable internal conditions

Which body system plays a significant role in maintaining homeostasis?
a) Nervous system
b) Respiratory system
c) Digestive system
d) Muscular system

Answer
a) Nervous system

Which of the following is an example of negative feedback in homeostasis?
a) Shivering to generate heat in cold weather
b) Sweating to cool down the body on a hot day
c) Consuming food to replenish energy levels
d) Accelerating the heart rate during exercise

Answer
a) Shivering to generate heat in cold weather

The body’s temperature is regulated by which part of the brain?
a) Cerebellum
b) Medulla oblongata
c) Hypothalamus
d) Amygdala

Answer
c) Hypothalamus

Which hormone is responsible for regulating glucose levels in the blood?
a) Insulin
b) Testosterone
c) Estrogen
d) Melatonin

Answer
a) Insulin

When blood sugar levels drop, what hormone is released to increase them?
a) Insulin
b) Glucagon
c) Thyroxine
d) Cortisol

Answer
b) Glucagon

Which of the following is NOT a method of heat loss during hot weather?
a) Sweating
b) Vasodilation
c) Shivering
d) Radiating heat from the skin

Answer
c) Shivering

Which organ is responsible for filtering and removing waste products from the blood?
a) Liver
b) Kidneys
c) Pancreas
d) Spleen

Answer
b) Kidneys

The process of maintaining a stable internal environment despite changes in the external environment is known as:
a) Metabolism
b) Homeostasis
c) Adaptation
d) Thermoregulation

Answer
b) Homeostasis

What is the primary role of the respiratory system in homeostasis?
a) Regulating body temperature
b) Transporting nutrients to cells
c) Removing carbon dioxide from the body
d) Producing hormones for growth

Answer
c) Removing carbon dioxide from the body

Which of the following is an example of a positive feedback loop in homeostasis?
a) Blood clotting after an injury
b) Sweating to cool down the body
c) Regulation of blood glucose levels
d) Maintaining constant body temperature

Answer
a) Blood clotting after an injury

In response to high blood pressure, the body may initiate a process to lower it. This is an example of:
a) Positive feedback
b) Negative feedback
c) Homeostatic imbalance
d) Adaptation

Answer
b) Negative feedback

The hormone responsible for the fight-or-flight response in stressful situations is:
a) Cortisol
b) Estrogen
c) Testosterone
d) Adrenaline (Epinephrine)

Answer
d) Adrenaline (Epinephrine)

What is the role of the skin in maintaining homeostasis?
a) Production of hormones
b) Regulation of body temperature
c) Pumping blood to the heart
d) Absorption of nutrients

Answer
b) Regulation of body temperature

When blood sugar levels rise, which hormone is released to decrease them?
a) Estrogen
b) Testosterone
c) Glucagon
d) Insulin

Answer
d) Insulin

Which part of the brain controls the secretion of hormones from the pituitary gland?
a) Hypothalamus
b) Cerebellum
c) Thalamus
d) Hippocampus

Answer
a) Hypothalamus

Which of the following is NOT a component of the feedback loop in homeostasis?
a) Sensor
b) Effector
c) Receptor
d) Stimulus

Answer
d) Stimulus

The process of breaking down complex substances into simpler forms for energy production is called:
a) Anabolism
b) Catabolism
c) Photosynthesis
d) Oxidation

Answer
b) Catabolism

The release of antidiuretic hormone (ADH) helps in the conservation of:
a) Water
b) Glucose
c) Sodium
d) Calcium

Answer
a) Water

The body’s internal temperature is typically around:
a) 50°C (122°F)
b) 37°C (98.6°F)
c) 25°C (77°F)
d) 10°C (50°F)

Answer
b) 37°C (98.6°F)

Which of the following is a response to low blood sugar levels?
a) Vasodilation
b) Sweating
c) Glycogen breakdown
d) Pupil constriction

Answer
c) Glycogen breakdown

Which organ regulates the body’s metabolism and plays a crucial role in maintaining
homeostasis?
a) Pancreas
b) Liver
c) Spleen
d) Gallbladder

Answer
b) Liver

The process of maintaining proper pH levels in the body is essential for:
a) Nerve function
b) Muscle contraction
c) Proper enzyme activity
d) All of the above

Answer
d) All of the above

Which of the following is an example of an internal stimulus that triggers homeostatic regulation?
a) A drop in environmental temperature
b) Feeling hungry before mealtime
c) Exposure to bright light
d) Physical injury to the skin

Answer
b) Feeling hungry before mealtime

The process of sweating is an example of the body’s response to:
a) Low blood pressure
b) High body temperature
c) Low blood sugar levels
d) High blood pressure

Answer
b) High body temperature

Which of the following is NOT a function of the urinary system in maintaining homeostasis?
a) Regulation of blood pressure
b) Removal of waste products
c) Production of red blood cells
d) Regulation of electrolyte levels

Answer
c) Production of red blood cells

Which hormone is responsible for calcium regulation in the blood?
a) Thyroxine
b) Insulin
c) Calcitonin
d) Glucagon

Answer
c) Calcitonin

What is the primary function of the hypothalamus in maintaining homeostasis?
a) Regulation of body temperature
b) Production of hormones
c) Digestion of food
d) Pumping blood to the heart

Answer
a) Regulation of body temperature

When blood sugar levels are high, the pancreas releases which hormone to lower them?
a) Insulin
b) Glucagon
c) Estrogen
d) Cortisol

Answer
a) Insulin

The body’s response to an increase in blood pressure involves:
a) Vasodilation
b) Decreased heart rate
c) Constriction of blood vessels
d) Release of adrenaline

Answer
c) Constriction of blood vessels

What is the purpose of vasoconstriction in maintaining homeostasis?
a) To decrease blood flow to vital organs
b) To increase blood flow to the extremities
c) To regulate body temperature
d) To reduce blood pressure

Answer
d) To reduce blood pressure

The process of shivering is a mechanism to:
a) Generate heat and increase body temperature
b) Cool down the body and lower temperature
c) Increase blood flow to the skin
d) Release excess energy from the body

Answer
a) Generate heat and increase body temperature

Which of the following is NOT a factor that can disrupt homeostasis?
a) Environmental changes
b) Hormonal regulation
c) Physical injury
d) Genetic factors

Answer
b) Hormonal regulation

The release of which hormone is responsible for increasing heart rate during times of stress or danger?
a) Estrogen
b) Insulin
c) Thyroxine
d) Adrenaline (Epinephrine)

Answer
d) Adrenaline (Epinephrine)

Which of the following statements is true about homeostasis?
a) It only occurs in animals, not in plants.
b) It involves keeping external conditions constant.
c) It is a static, unchanging process.
d) It helps maintain stable internal conditions.

Answer
d) It helps maintain stable internal conditions.

The primary organ responsible for detoxifying harmful substances in the body is the:
a) Liver
b) Kidneys
c) Lungs
d) Pancreas

Answer
a) Liver

Which of the following is an example of an external stimulus that triggers homeostatic regulation?
a) Feeling thirsty after eating salty food
b) Sweating during exercise
c) Increased heart rate during stress
d) Feeling sleepy after a long day

Answer
b) Sweating during exercise

The body’s response to low blood pressure involves:
a) Vasodilation
b) Increased heart rate
c) Constriction of blood vessels
d) Release of insulin

Answer
b) Increased heart rate

The process of converting glucose into energy with the help of oxygen is known as:
a) Fermentation
b) Glycolysis
c) Cellular respiration
d) Photosynthesis

Answer
c) Cellular respiration

Which hormone is responsible for stimulating water reabsorption in the kidneys?
a) Insulin
b) Glucagon
c) Aldosterone
d) Thyroxine

Answer
c) Aldosterone

Which of the following is a response to high blood sugar levels?
a) Glycogen breakdown
b) Vasodilation
c) Pupil dilation
d) Release of adrenaline

Answer
a) Glycogen breakdown

The body’s response to an increase in body temperature involves:
a) Sweating
b) Shivering
c) Constriction of blood vessels
d) Release of glucagon

Answer
a) Sweating

The hormone responsible for increasing blood sugar levels during times of stress or danger is:
a) Thyroxine
b) Insulin
c) Cortisol
d) Glucagon

Answer
c) Cortisol

The process of maintaining the balance of water and electrolytes in the body is primarily controlled by the:
a) Liver
b) Kidneys
c) Pancreas
d) Heart

Answer
b) Kidneys

Which of the following is an example of an effector in a homeostatic feedback loop?
a) The brain
b) The heart
c) The lungs
d) The sweat glands

Answer
d) The sweat glands

The hormone responsible for increasing blood sugar levels by stimulating the breakdown of glycogen in the liver is:
a) Glucagon
b) Insulin
c) Thyroxine
d) Estrogen

Answer
a) Glucagon

When blood pressure decreases, the body may initiate a process to raise it. This is an example of:
a) Positive feedback
b) Negative feedback
c) Homeostatic imbalance
d) Adaptation

Answer
b) Negative feedback

The hormone responsible for increasing heart rate and blood flow to the muscles during exercise is:
a) Insulin
b) Estrogen
c) Testosterone
d) Adrenaline (Epinephrine)

Answer
d) Adrenaline (Epinephrine)

Which of the following is an example of a disruption in homeostasis?
a) The body sweating to cool down on a hot day
b) The body increasing heart rate during exercise
c) The body shivering to generate heat in cold weather
d) The body releasing insulin to lower blood sugar levels

Answer
d) The body releasing insulin to lower blood sugar levels

The process of maintaining a stable internal environment through physical and behavioral changes is called:
a) Adaptation
b) Evolution
c) Metabolism
d) Homeostasis

Answer
a) Adaptation

The body’s response to high blood sugar involves:
a) Vasodilation
b) Glycogen breakdown
c) Constriction of blood vessels
d) Increased heart rate

Answer
b) Glycogen breakdown

The process of converting nutrients into complex molecules for growth and repair is known as:
a) Anabolism
b) Catabolism
c) Fermentation
d) Photosynthesis

Answer
a) Anabolism

Which hormone is responsible for stimulating the breakdown of fat cells and increasing blood glucose levels?
a) Glucagon
b) Insulin
c) Thyroxine
d) Cortisol

Answer
d) Cortisol

The process of maintaining a stable internal environment is crucial for the proper functioning of which of the following systems?
a) Nervous system
b) Immune system
c) Endocrine system
d) All of the above

Answer
d) All of the above

The body’s response to low body temperature involves:
a) Sweating
b) Vasodilation
c) Constriction of blood vessels
d) Shivering

Answer
d) Shivering

The hormone responsible for lowering blood sugar levels by promoting glucose uptake by cells is:
a) Glucagon
b) Insulin
c) Estrogen
d) Thyroxine

Answer
b) Insulin

Which of the following is a response to low blood pressure?
a) Increased heart rate
b) Constriction of blood vessels
c) Sweating
d) Vasodilation

Answer
a) Increased heart rate

The process of converting light energy into chemical energy in plants is known as:
a) Anabolism
b) Catabolism
c) Photosynthesis
d) Respiration

Answer
c) Photosynthesis

The body’s response to high body temperature involves:
a) Sweating
b) Shivering
c) Constriction of blood vessels
d) Vasodilation

Answer
a) Sweating

The hormone responsible for stimulating the release of glucose from the liver into the bloodstream is:
a) Thyroxine
b) Insulin
c) Estrogen
d) Glucagon

Answer
d) Glucagon

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