Tag: science & technology

Modern commercial and military aircraft primarily use gas turbine engines, including turbofans, turbojets, turboprops, and turboshafts. Gas turbines offer superior power-to-weight ratio, fuel efficiency at high altitudes, and reliability compared to piston engines. Piston engines are largely confined to small general aviation aircraft today.

The national bird of Finland is the Whooper Swan (Cygnus cygnus). It's a large white swan species native to northern Eurasia and has been Finland's national bird since 1981. The Barn Swallow is the national bird of Austria, White Stork of Lithuania, and Great Bustard of Hungary.

None of the listed options is Singapore's national bird. Singapore's national bird is the Crimson Sunbird (Aethopyga siparaja). The Bald Eagle is the USA's national bird, Purple Finch is a North American species (not a national bird), and Troupial is Venezuela's national bird. Therefore, 'None of the above' is correct.

The national bird of Mexico is the Crested Caracara (Caracara cheriway), a bird of prey found in Central and South America. Note: Option B appears to have a typo ('Carara' instead of 'Caracara'). The American Robin is the national bird of the USA, American Goldfinch of Iowa (USA), and California Gull of Utah (USA).

The Black Crowned-Crane is the national bird of Nigeria. This large, elegant bird is native to Africa and is prominent in Nigerian culture and symbolism.

The Common Loon (also known as the Great Northern Loon) is Canada's national bird. It was officially adopted as a national symbol in 1987 and appears on the Canadian one-dollar coin (the 'loonie').

The lungs are situated in the thoracic cavity, which is the chamber of the body located above the diaphragm. The thoracic cavity is bounded by the rib cage and contains the lungs, heart, and other organs. The abdominal cavity contains digestive organs, pericardial cavity surrounds the heart, and buccal cavity is the mouth cavity.

Human somatic cells contain 46 chromosomes, organized as 23 pairs - one set from each parent. This includes 44 autosomes and 2 sex chromosomes (XX or XY). The 23 chromosome count refers only to the chromosome types in a haploid set (gametes), not the total in body cells.

Enzymes are biological catalysts that speed up chemical reactions in the body. They are most prominently involved in digestion, where they break down complex food molecules into simpler, absorbable nutrients in the digestive tract.

While digestion begins in the stomach through acid and enzyme action, the majority of digestion and nearly all nutrient absorption occurs in the small intestines. The small intestines have a huge surface area with villi and microvilli to maximize absorption.