Biology MCQs

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Arthropoda is the largest phylum of animal kingdom because around 2/3rd of all the named species on Earth belong to this phylum.
Ants, mosquitoes, flies, cockroaches, shrimp, crabs, spiders, scorpions etc. are examples of arthropods. There are three main classes of arthropods as follows:

• Insects: This includes mosquitoes, cockroaches, ants, flies, bees, moths, grasshoppers, beetles and butterflies
• Crustaceans: This includes crabs, lobsters, shrimp and barnacles
• Arachnids: This includes scorpions, spiders and mites

Further, a few other classes are onychophorans (velvet worms), diplopods (millipedes) and chilopods (centipedes).

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Arsenicosis or Black foot is caused by exposure over a period of time to Arsenic in drinking water. It may also be due to intake of arsenic via food or air. Kindly note that Itai-itai disease is caused by Cadmium poisoning.

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Skin works as a respiratory organ in frog. The frog has three respiratory surfaces on its body which it uses to exchange gas with its surroundings: the skin, in the lungs and on the lining of the mouth.

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When the body’s immune system cells destroy the insulin producing beta cells of the pancreas is termed as Type 1 diabetes. Symptoms may include increased thirst, frequent urination, hunger, fatigue and blurred vision.

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Posterior region of skull is the right location of foramen magnum. The foramen magnum refers to a large oval opening (foramen) in the occipital bone of the skull in humans and as well as many other animals.

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Blue component in light causes suppression of melatonin produced by the pineal gland. Melatonin regulates the sleep–wake cycle. Natural levels of melatonin in the blood are highest at night.

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Pigeons have become useful bioindicators for lead pollution due to their widespread presence in cities and their ability to accumulate and retain heavy metals, including lead, in their tissues. Researchers have found that the feathers, blood, and tissues of pigeons can provide valuable information about the levels of lead exposure in the environment.

Lead pollution in cities can come from various sources, including lead-based paints, industrial emissions, and traffic-related sources. Pigeons, being urban birds, are exposed to these sources and can accumulate lead over time. By studying lead levels in pigeon populations, scientists can gain insights into the extent of lead pollution in a city and assess its potential risks to both wildlife and humans.

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Dendrochronology is the branch of biology which studies and estimates the age of woody plants.

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Dehydration is a deficiency of water in thebody. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics maycause dehydration. People feel thirsty, and asdehydration worsens, they may sweat less and excrete less urine.

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The connective tissues include several types of fibrous tissue that vary only in their density and cellularity, as well as the more specialized and recognizable variants—bone, ligaments, tendons, cartilage, and adipose tissue. Skin is not a connective tissue. It is the body’s largest organ and consists of multiple layers, including the epidermis (outermost layer) and the dermis (deeper layer). Skin primarily serves as a protective barrier and regulates temperature, but it is mainly classified as an epithelial tissue due to its structure and function.