Biology MCQs

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Composting is the depomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for enriching soil. It is the chief way to recycle wastes.

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Pneumatic bone is hollow bone filled with air, connected to the respiratory system. Many of a bird’s bones are pneumatic as an adaptation to flying. For flight to occur in Aves, four physical forces (thrust and drag, lift and weight) must work together. In order for birds to balance these forces, certain physical characteristics are required. Which most of the flying birds have acquired in one way or other.

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Enzymes are sometimes called biological catalysts because they speed up reactions, and only small amounts are required. Digestive enzymes speed up the breakdown of complex food substances into simpler subunits. The breakdown of food in digestion is actually caused by water chemically splitting the complex food molecules, a process called hydrolysis.

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Sponges are sedantric, diploblastic, asymmetrical animals, once considered plants. They are characterized by the water canal system with pores called the ostia and osculum. They are also known to posses the multipurpose cells called chanocytes.

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Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; the diseases can be spread, directly or indirectly, from one person to another. Tuberculosis (TB), infectious disease that is caused by the Tubercle bacillus, Mycobacterium tuberculosis. Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus Cholera is an infectious disease that causes severe watery diarrhea, which can lead to dehydration and even death if untreated. Diabetes mellitus, commonly known as diabetes, is a metabolic disease that causes high blood sugar. The hormone insulin moves sugar from the blood into your cells to be stored or used for energy.

Notes:
Bile is a fluid that is produced continuously by the liver and stored and concentrated in the gall bladder. After eating, this stored bile is discharged into the duodenum. Bile helps with digestion by breaking down fats into fatty acids, which can be taken into the body by the digestive tract.

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Edward Jenner of Britain discovered vaccination in 1796. Louis Pasteur of France discovered Rabies vaccine in 1860. Robert Koch of Germany discovered Cholera and TB germs in 1877. Sir Ronald Ross was a British Physician and entomologist, noted for identifying the links between mosquitoes and malaria. He was born in India in 1857 at Almora.

Notes:
More than one option is correct. Jatropha curcas is known for its insecticidal, pesticidal and fungicidal properties. It is used in rural Bengal for dhobi itch (a common fungal infection of the skin). Pesticidal properties have also been reported from Pongamia Pinnata (Karanja) especially against nematodes.

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In cockroach, an arthropod belonging to class Insecta, the respiratory system includes openings called spiracles present in abdominal surface. These opening are further connected with trachea, trachioles and bronchioles to direct allow the atmospheric air to interact with body cells for gaseous exchange. Therefore, cockroach with its abdomen immersed in water die of oxygen starvation.

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Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue. Each hemoglobin molecule is made up of four heme groups surrounding a globin group. Heme contains iron and gives a red color to the molecule.