Tag: science & technology

Normal human body temperature is approximately 37°C (98.6°F), though it can vary slightly throughout the day and from person to person. 36.9°C is within the normal range. 81.1°C is lethally hot (well above boiling), 21.7°C is dangerously cold (hypothermia range), and 98.6°C is body temperature in Fahrenheit, not Celsius.

Vitamin K is essential for blood clotting as it helps produce clotting factors (proteins) in the liver. Without adequate Vitamin K, blood cannot clot properly, leading to excessive bleeding. Vitamin B1 (thiamine) helps with nerve function, Vitamin B2 (riboflavin) aids energy production, and Vitamin D supports bone health and calcium absorption.

The average adult human body contains approximately 5-6 liters of blood, which is about 7-8% of total body weight. This volume is essential for transporting oxygen, nutrients, hormones, and waste products throughout the body. Options A and B are too low, while options C and D exceed physiological limits.

Red blood cells (erythrocytes) are produced in the bone marrow through a process called erythropoiesis. In adults, this primarily occurs in the vertebrae, sternum, ribs, and pelvic bones. The liver produces RBCs only during fetal development, while kidneys and heart have no role in RBC production.

An adult human skeleton typically contains 206 bones, which decrease from approximately 270 bones at birth due to fusion of separate bones during growth. The axial skeleton has 80 bones while the appendicular skeleton has 126 bones. Options A, B, and D are incorrect counts.

The pancreas secretes insulin from beta cells of the islets of Langerhans to regulate blood glucose levels. It also produces glucagon (from alpha cells) and digestive enzymes. Bile juice is produced by the liver, not the pancreas. Peptic juice refers to gastric secretions from the stomach.

The tibia (shinbone) is the larger and stronger of the two bones in the lower leg, connecting the knee to the ankle. It bears most of the body's weight. The fibula is the smaller leg bone. The skull contains cranial and facial bones, while arm bones include humerus, radius, and ulna.

The cerebrum is the largest part of the human brain, making up about 85% of brain weight. It is responsible for higher cognitive functions including thinking, memory, language, and sensory processing. The cerebellum coordinates movement, while the medulla oblongata controls vital autonomic functions like breathing and heart rate.

Calcium phosphate, specifically in the form of hydroxyapatite, is the primary mineral component of bones and teeth, providing hardness and strength. Bones are about 60-70% mineral (mainly calcium phosphate) and 30-40% organic matrix (collagen). Calcium carbonate is found in seashells, calcium sulfate in gypsum, and calcium nitrate is used in fertilizers.