General Science Questions (MCQs) for Competitive Examinations

Notes:
Femur (thighbone) the longest bone in human body. Its average length is 19.9 inch. The femur is the only bone in the thigh. Tibia (shin bone) and Fibula (lower leg) come next in sequence with length of 16.9 and 15.9 inch respectively.

Notes:
Gambusia affinis, also known as Mosquito fish, is a species of freshwater fish that is introduced directly into ecosystems as a biocontrol to lower mosquito populations. The diet of this fish sometimes consists of large numbers of mosquito larvae. Gambusia affinis has turned out to be indispensable to modern Mosquito/Malaria control programs in countries such as Iran.

Notes:
‘Survival of the fittest’ is a phrase that originated from Darwinian evolutionary theory as a way of describing the mechanism of natural selection. Herbert Spencer first used the phrase, after reading Charles Darwin’s On the Origin of Species, in his Principles of Biology (1864), in which he drew parallels between his own economic theories and Dar-win’s biological ones.

Notes:
A vein is an elastic blood vessel that transports blood from various regions of the body to the heart. Veins are components of the cardiovascular system, which circulates blood to provide nutrients to the cells of the body. Veins can be categorized into four main types: pulmonary, systemic, superficial, and deep veins.

Notes:
There are three types of heterotrophs: herbivores, carnivores and omnivores. Also referred to as consumers, heterotrophs are organisms that obtain their energy from organic compounds. In other words, they are organisms that are unable to produce their own food (unlike autotrophs) and therefore have to consume/ ingest organic compounds as a source of energy.

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Vitamin C also known as ascorbic acid is found in citrus fruit such as orange, lemon, lime, grapefruit, grapes etc. It protects the immune system, reduces the severity of allergic reactions and helps fight off infections.

Notes:
Insect and bird wings are analogous structures but not homologous structures. They are externally similar in appearance and function (i.e. for flying), but have dissimilar origin and developmental plan.

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The bee hummingbird, also known as Helena hummingbird, is a species of hummingbird which is the world’s smallest bird. Females weigh 2.6 g and are 6.1 cm long, and are slightly larger than males, with an average weight of 1.95 g and length of 5.5 cm. As its name suggests, it is scarcely larger than a bee. It is endemic to Cuba and the Isla de la Juventud.

Notes:
Medulla Oblongata is that part of the brain which regulates basic functions. It regulates vomiting, hiccupping, swallowing, coughing, sneezing, etc.

Notes:
The femur (pl. femurs or femora), or thigh bone, is the most proximal (closest to the center of the body) bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in the rear legs. By most measures the femur is not only the largest but also other of the strongest bones in the body head of the femur articulates with the acetabulum.