Biology

The average weight of a man's brain is approximately 4.8 ounces, while the average weight of a woman's brain is slightly less, around 4.4 ounces. This difference is well-documented in anatomical studies.

Metabolism encompasses all chemical processes in the body, including absorption, assimilation, and secretion, making it the process that includes all the others listed.

The thyroid gland is shaped like a butterfly, with two lobes connected by a narrow isthmus, located in the neck. This distinctive shape differentiates it from the pituitary, adrenal, and pineal glands, which have different forms.

Authoritative sources including the Smithsonian's National Zoo and other wildlife organizations indicate that a Grevy's zebra typically has about 80 stripes in total, which implies roughly 40 stripes on each side. This is significantly more than 36 stripes per side. Therefore, the correct answer is '80+' stripes per side, corresponding to option C. The original answer '36+' is an underestimate and not supported by reliable sources.

The cornea is the only living tissue in the body that does not have a direct blood supply. It receives nutrients and oxygen through tears and aqueous humor, unlike other tissues that rely on blood vessels.

Giraffes do not have vocal cords, which is why they are generally silent and produce very few sounds. In contrast, lions, zebras, and dolphins all have vocal cords and use them to produce various sounds.

Photoreceptors, which detect light, are located in the retina of the eye. The retina contains rods and cones that convert light into neural signals for vision.

Vitamin B12 is essential for the production of new red blood cells, and the liver stores and utilizes it in this process. Therefore, the liver uses vitamin B12 for creating new red blood cells.

A cataract is the clouding of the lens in the eye that obstructs light passage, leading to impaired vision. This matches the description given in the question, making option C correct.

The nervous system primarily consists of the brain, spinal cord, and neurons, which are the fundamental components responsible for processing and transmitting information throughout the body.

A biopsy is a medical procedure where tissue is taken from the human body to examine it for disease, especially cancer. While animals can also have biopsies, the term is most commonly associated with human medical diagnostics, making 'Human body' the best answer here.

Trypsin is a protein-digesting enzyme produced by the pancreas, not the stomach. It is secreted into the small intestine where it helps break down proteins.

Vitamin C is a water-soluble vitamin that cannot be stored in the human body in significant amounts, unlike fat-soluble vitamins such as vitamin D and K which can be stored in body fat and liver. Therefore, vitamin C must be regularly consumed in the diet.

The pancreas functions as both an endocrine gland by secreting hormones like insulin into the bloodstream, and as an exocrine gland by producing digestive enzymes released into the small intestine. The thyroid and parathyroid glands are solely endocrine glands.

Tropism is the growth response of a plant in a particular direction due to an external stimulus, such as light or gravity, making option B correct.

Leukocytes, or white blood cells, are responsible for protecting the body against infectious diseases and foreign invaders by identifying and destroying pathogens. Red blood cells carry oxygen, while the endoplasmic reticulum and Golgi apparatus are cellular organelles involved in protein and lipid processing, not immune defense.

Earthworms do not have eyes; instead, they sense light and vibrations through their skin. Therefore, the correct answer is that earthworms have no eyes.

Botany is the scientific study of plants, and it is also known as Phytology. Phycology is the study of algae, Pedology is the study of soils, and Plantophyta is not a correct term for botany.

The hypothalamus is the part of the brain responsible for regulating thirst and hunger by maintaining homeostasis and controlling the release of hormones related to these drives.

Hepatitis C is a viral infection that primarily affects the liver and is a leading cause of chronic liver disease, including cirrhosis and liver cancer. It is not related to HIV, diabetes, or AIDS.

Elephants have the longest gestation period among land animals, lasting about 640 to 660 days (approximately 95 weeks). This is significantly longer than other land mammals, making option B correct.

A rhinoscope (or nasoscope) is specifically designed to examine the inside of the nose, making option B the correct answer. It is a thin, tube-like instrument used by medical professionals to inspect nasal passages.

The masseter muscle, located in the jaw, is considered the strongest muscle in the human body relative to its weight because it can exert a very high force for its size, enabling powerful biting and chewing.

The human heart is a myogenic heart, meaning its contractions originate from the heart muscle itself rather than from nervous stimulation. This intrinsic rhythmicity distinguishes it from neurogenic hearts, which rely on nervous input to beat.

The white bellbird (Procnias albus) is recognized as the world's loudest bird, with calls reaching up to 125 decibels, louder than a rock concert. This surpasses the loudness of peacocks and pihas, making option A correct.