Biology Past Paper PDF

1.⁠ ⁠*What is the definition of homeostasis?* - a) The regulation of an organism's size. - *b) The maintenance of a constant internal environment.* - c) The process of photosynthesis in plants. - d) The breakdown of food in the digestive system. 2.⁠ ⁠*Which part of the body serves as the control...

1.⁠ ⁠*What is the definition of homeostasis?* - a) The regulation of an organism's size. - *b) The maintenance of a constant internal environment.* - c) The process of photosynthesis in plants. - d) The breakdown of food in the digestive system. 2.⁠ ⁠*Which part of the body serves as the control center for thermoregulation?* - a) Lungs - b) Heart - *c) Hypothalamus* - d) Liver 3.⁠ ⁠*What is osmoregulation?* - a) The process of breathing. - b) The maintenance of a stable body temperature. - *c) The regulation of water content in the body.* - d) The breakdown of glucose for energy. 4.⁠ ⁠*Which of the following is NOT a mechanism for heat production in the body?* - *a) Sweating* - b) Shivering - c) Increased metabolism - d) Hormonal release (e.g., thyroxine) 5.⁠ ⁠*How does the body respond to cold exposure?* - a) Increased sweating - b) Vasodilation  - *c) Shivering and reduced skin blood flow* - d) Increased skin blood flow 6.⁠ ⁠*In blood glucose regulation, which organ plays a key role in maintaining glucose levels?* - a) Heart - b) Kidneys - *c) Pancreas* - d) Lungs 7.⁠ ⁠*What is the role of negative feedback in homeostasis?* - a) To amplify changes in the body’s internal environment. - *b) To counteract changes and bring the body back to its set point.* - c) To cause the body to lose more heat. - d) To increase the amount of water in cells indefinitely. 8.⁠ ⁠*What is the eXect of heat acclimatization on sweat rate?* - a) Decreases sweat rate - *b) Increases sweat rate* - c) Eliminates sweating entirely - d) Has no eXect on sweat rate 9.⁠ ⁠*Why is it essential for the body to maintain stable blood pressure, CO2 levels, and body temperature?* - a) To allow the body to grow larger. - *b) To avoid cell damage and ensure normal physiological functions.* - c) To improve muscle strength. - d) To regulate sleep patterns. 10.⁠ ⁠*Which hormone is involved in the body’s response to cold by increasing heat production?* - a) Insulin - *b) Thyroxine* - c) Estrogen - d) Cortisol 11.⁠ ⁠*How does the body respond to overheating?* - a) Shivering and increasing metabolic rate. - *b) Sweating and vasodilation.* - c) Vasoconstriction and increased skin blood flow. - d) Decreased respiration rate. 12.⁠ ⁠*What happens during negative feedback regulation when CO2 levels rise during exercise?* - a) The body stops producing CO2. - *b) Breathing rate increases to exhale more CO2.* - c) Breathing rate decreases to conserve energy. - d) Heart rate decreases. 13.⁠ ⁠*Which of the following processes is an example of a negative feedback loop in the human body?* - a) Blood clotting - b) Childbirth - *c) Thermoregulation* - d) Muscle contraction during exercise 14.⁠ ⁠*Which of the following is a long-term response to heat exposure that helps the body adapt?* - *a) Increased plasma volume* - b) Decreased sweating - c) Increased sodium chloride loss in sweat - d) Reduced core temperature 15.⁠ ⁠*What would happen if the water content in cells is not properly regulated?* - *a) Cells could burst from too much water.* - b) Cells would increase metabolic activity. - c) Cells would adapt without harm. - d) Cells would become more eXicient at energy production. 16.⁠ ⁠*Which system is primarily responsible for regulating oxygen and carbon dioxide levels in the body?* - a) Digestive system - b) Nervous system - *c) Respiratory system* - d) Muscular system 17.⁠ ⁠*What is the role of catecholamines (like adrenaline) in thermoregulation?* - a) Reduce body temperature by increasing sweating. - *b) Increase heat production by stimulating metabolic processes.* - c) Slow down the body’s metabolic rate. - d) Decrease heart rate to conserve energy. 18.⁠ ⁠*What term refers to the body's ability to adapt to long-term cold exposure?* - a) Heat tolerance  - *b) Cold acclimatization* - c) Thermogenesis - d) Vasodilation 19.⁠ ⁠*How is blood pressure regulated in the body?* - a) By the digestive system - *b) Through negative feedback mechanisms involving baroreceptors* - c) By the muscular system contracting to pump blood - d) Through the production of glucose in the liver 20.⁠ ⁠*Which physiological condition is controlled through osmoregulation?* - a) Body temperature - b) Blood glucose levels - *c) Water and salt balance* - d) Blood oxygen levels