Human Physiology and Anatomy

Hemoglobin is the iron-containing protein in red blood cells responsible for carrying oxygen from the lungs to body tissues and returning carbon dioxide. This oxygen transport function is essential for cellular respiration. Hemoglobin does not directly prevent or cause anemia - it's the molecule whose deficiency causes anemia.

Taking a single step activates approximately 200 muscles throughout your body. This includes muscles in your legs for the actual movement, core muscles for balance and stability, back muscles for posture, and even arm muscles for natural swinging motion. Walking is a complex full-body coordination activity.

Taking a single step forward requires using approximately 200 muscles throughout your body. This is identical to question 113002 and includes leg muscles for propulsion, core muscles for stability, back muscles for posture, and arm muscles for natural balance-maintaining movement.

Perspiration (sweating) is the body's main cooling mechanism - as sweat evaporates from the skin, it removes heat and helps regulate body temperature. Respiration is for breathing, mastication is chewing, and urination is for eliminating waste.

Teething and diarrhoea are coincidental events in infancy, not causally related. The belief that teething causes diarrhoea is a myth - infections or dietary changes cause diarrhoea, not tooth eruption.

Ligaments are tough, fibrous connective tissues that connect bones to other bones at joints, providing stability and limiting excessive movement. They are different from tendons, which connect muscles to bones. Option A is incorrect because muscles connect to bones via tendons, not ligaments.

Tendons connect muscles to bones, transmitting muscle contractions to bones to create movement. They are different from ligaments, which connect bones to other bones. Option B is incorrect because tendons do not connect bones directly to each other.

The human brain actually consumes about 20 watts of power, not 300-400 watts. The brain uses about 20% of the body's total energy despite being only 2% of body weight, but this amounts to roughly 20 watts, not hundreds of watts. The claim in the question is greatly exaggerated.

Kidneys filter blood and remove metabolic wastes like urea, creatinine, and excess salts through urine formation. While kidneys also help regulate blood pressure via the renin-angiotensin system, waste removal is their primary function. Body temperature is regulated by the hypothalamus and sweat glands in the skin, not kidneys.

Hemoglobin is a protein in red blood cells that binds oxygen in the lungs and transports it to body tissues. It gives blood its red color and is essential for aerobic respiration. Hemoglobin does not destroy bacteria (that's white blood cells), prevent anemia (it actually causes anemia when deficient), or directly utilize energy.

Bones provide attachment points for muscles (A), protect vital organs like the brain and heart (B), and produce blood cells in bone marrow (D). However, hormone secretion for calcium regulation is done by the parathyroid gland and calcitonin from the thyroid gland, not by bones themselves - though bone tissue responds to these hormones.

The alpha cells of islets of langerhans secrete glucagon.

Nervous system and endocrine system are very closely related because both need stimuli for their action response.

The main function of beta cells of pancreas is production of insulin.