Biology

Chromosomes first become visible during prophase as the chromatin condenses into distinct, visible chromosomes. This is the earliest stage in mitosis where chromosomes can be clearly seen under a microscope.

Cancer treatment commonly involves chemotherapy and radiotherapy, which target and kill cancer cells. Antibiotics and vaccines are not standard treatments for cancer.

The muscles located at the back of the thigh are known as the hamstrings. They include the biceps femoris, semitendinosus, and semimembranosus muscles, which are responsible for knee flexion and hip extension.

Anti Diuretic Hormone (ADH) is secreted by the posterior pituitary gland, which regulates water balance in the body by controlling the amount of water reabsorbed by the kidneys.

Gastrin is a hormone that stimulates the secretion of gastric acid in the stomach, not a digestive enzyme. Pepsin, trypsin, and ptyalin are all enzymes involved in the digestion of proteins and carbohydrates.

Bone remodeling involves osteoblasts, which build new bone; osteoclasts, which resorb bone; and osteocytes, which regulate the process and maintain bone tissue. Therefore, all these cell types participate in bone remodeling.

A chicken egg is a single cell, known as an ovum, which is one of the largest cells visible to the naked eye. It is not composed of multiple cells but is a single cell containing the yolk and surrounded by the egg white and shell.

Hepatitis A is primarily transmitted through the fecal-oral route, meaning it spreads via ingestion of food or water contaminated with feces from an infected person. Therefore, 'Faeces' is the correct answer, not 'Water' alone.

Myopia, or nearsightedness, occurs when the eye focuses images in front of the retina. It is corrected using concave lenses, which diverge light rays so they focus correctly on the retina.

Glutamic acid is an amino acid, which is a fundamental biomolecule involved in protein synthesis. The other acids listed are organic acids but are not classified as biomolecules essential to living organisms.

Plants have cellulose in their cell walls, which provides structural support, while animals lack cellulose. This distinguishes plant cells from animal cells.

The development of calf muscles in ladies who wear high heel sandals is an example of 'use and disuse of organ,' where frequent use of certain muscles leads to their development. This is a concept from Lamarckian theory, not artificial selection, which involves human-directed breeding.

The term for an abnormally great desire for food and excessive eating is 'polyphagia' or 'hyperphagia.' These terms describe an intense, often insatiable hunger that persists despite eating and may lead to continual food-seeking behavior. Polyphagia is a symptom commonly associated with conditions such as diabetes, hyperthyroidism, and certain genetic disorders like Prader-Willi syndrome. 'Bulimia nervosa' is an eating disorder characterized by episodes of binge eating followed by compensatory behaviors like purging, and does not simply mean excessive eating. 'Dysphagia' refers to difficulty swallowing, and 'phagia' alone means eating or swallowing in general, not excessive eating. Therefore, none of the options A, B, or C correctly define the term for excessive eating or abnormally great desire for food, making 'None of the above' the correct answer.

Cancer is commonly treated using chemotherapy and radiotherapy, which target and kill cancer cells. Antibiotics and vaccines are not standard treatments for cancer.

The Zika virus was first identified in the Zika Forest of Uganda in 1947, which is why it was named after this location.

Female ova (egg cells) are haploid because they contain half the number of chromosomes of a diploid cell, which allows for the restoration of the diploid number upon fertilization.

Food typically remains in the small intestine for about 2 to 6 hours, where most nutrient absorption occurs before moving to the large intestine.

The average weight of a human male brain is approximately 1350 grams, which is supported by anatomical studies. This makes option C the correct choice.

The spinal cord is divided into cervical, thoracic, lumbar, sacral, and coccygeal regions. 'Pelvic' is not a recognized region of the spinal cord, making option C the correct answer.

The spinal cord primarily controls reflex activities, which are automatic and rapid responses to stimuli, without involving the brain. It does not control thinking activities or sexual activities directly.

Pantothenic acid is the chemical name for vitamin B-5, which is essential for synthesizing coenzyme A and metabolizing fats, carbohydrates, and proteins.

Fat digestion primarily occurs in the small intestine where bile from the liver emulsifies fats and pancreatic enzymes break them down for absorption.

Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene, leading to abnormal red blood cells. It is not caused by viruses, bacteria, or vitamin deficiency.

The pupil of the eye does not grow in size after birth; it changes size temporarily to regulate light entry but its physical size remains constant. Other organs like the kidney and liver grow as the body grows.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are primarily made up of proteins, which are chains of amino acids folded into specific shapes necessary for their function.