Biology MCQs

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Plasma is 55% of the blood by volume and constitutes 5% of the body weight. Plasma is a pale yellow transparent clear fluid which consists of 90-92% water and 8-10% organic and inorganic substances. Organic substances are mainly plasma proteins viz. albumin, globulin, prothrombin and fibrinogen. Albumins are responsible for maintenance of osmotic pressure of Blood. Globulins are chief sites for formation of antibodies; while prothrombin and fibrinogen are essential for clotting of blood

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All the species listed are water-dwelling creatures. However, a fundamental difference is that fish belong to the group of vertebrates, meaning their body possesses a spinal column. In contrast, crabs, prawns, and snails are invertebrates, denoting that they lack a backbone. Specifically, crabs and prawns are crustaceans, within the larger class of invertebrates, characterised by their exoskeleton and segmented bodies. Snails are grouped as molluscs, also a class of invertebrates, known for their soft unsegmented body. Hence, in this context, fish are different from the others.

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Fraternal twins are also called as dizygotic twins. In this type of pregnancy two eggs are independently fertilized by two different sperm cells. These types of twins may be of the same or different sexes.

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Atropa belladonna, commonly known as belladonna or deadly nightshade, is a poisonous perennial herbaceous plant in the nightshade family Solanaceae. Allium cepa, Allium sativum and Asparagus officinalis are food plants.

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Red blood cells (RBCs) have an average lifespan of 100-120 days and are produced in the bone marrow, while the spleen is where they are broken down. Macrophages break down RBCs into globin and heme, recycling amino acids and iron for various purposes, including protein synthesis. Some parts of old RBCs are reused in creating new ones. The average lifespan of cells in the human body is 7 to 10 years, but it varies across cell types and organs. Neutrophil cells, for example, last about two days.

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Pearls are composed primarily of calcium carbonate, which is what gives them their unique luster. They are formed within the shell of certain mollusks as a defense mechanism against a potentially threatening irritant, such as a parasite. Over time, the mollusk continually deposits layers of calcium carbonate, which eventually forms a smooth, hard pearl. This process can take up to eight years.

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Cornea does not have blood vessels. It is the transparent part of the eye that covers the front portion of the eye. It covers the pupil, iris, and anterior chamber.

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The phenomenon that causes animals to sweat to reduce temperature and change electrolyte concentration is homeostasis. When core body temperature increases, sweat glands respond by cooling the skin. Blood vessels also dilate, which allows the body to release more heat. Sweating is a rare ability in the animal kingdom. For example, rats don’t sweat when their core body temperature rises to 41°C. However, they do sweat in response to pilocarpine and other cholinergic agonists.

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All of the above are correct

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AB +ve is the universal acceptor blood group or the universal receptors. Because AB+ individuals have all of the possible antigens and therefore are the universal acceptors as their immune system is used to seeing each of the antigens.