Biology

211. The three primary soil micro-nutrients are

The three primary soil micro-nutrients are

[amp_mcq option1=”carbon, oxygen and water” option2=”copper, cadmium and carbon” option3=”nitrogen, phosphorus and potassium” option4=”boron, zinc and magnesium” correct=”option3″]

This question was previously asked in
UPSC CAPF – 2013
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The correct option is C. Nitrogen, Phosphorus, and Potassium are the three primary macronutrients required by plants.
Plants require various nutrients from the soil for healthy growth. These are broadly classified into macronutrients (needed in larger quantities) and micronutrients (needed in smaller quantities). The three most crucial macronutrients, often called primary nutrients, are Nitrogen (N), Phosphorus (P), and Potassium (K). While the question asks for “micro-nutrients”, option C lists the standard “primary” nutrients. Given the options, NPK is the only plausible set of primary nutrients listed.
Other macronutrients include Calcium (Ca), Magnesium (Mg), and Sulfur (S). Micronutrients include Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), and Chlorine (Cl). Option D lists some micronutrients, but NPK are universally referred to as the primary nutrients. The question’s wording “primary soil micro-nutrients” might be slightly imprecise, potentially intending to ask for primary nutrients or listing common soil nutrients from which to choose the primary ones. In the context of soil fertility and fertilizers, NPK are the standard primary nutrients.

212. Byssinosis disease is common in the workers of

Byssinosis disease is common in the workers of

[amp_mcq option1=”rubber industry” option2=”ceramic industry” option3=”textile industry” option4=”iron and steel industry” correct=”option3″]

This question was previously asked in
UPSC CAPF – 2012
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The correct answer is C) textile industry.
Byssinosis, also known as “brown lung disease,” is an occupational lung disease caused by inhaling cotton, flax, or hemp dust. It is commonly found among workers in the textile industry, particularly those involved in the initial processing of cotton fibers.
Workers in the rubber industry may face risks from chemicals or latex. Ceramic industry workers may be exposed to silica dust (silicosis). Iron and steel industry workers may be exposed to metal fumes, dusts, and heat. Byssinosis is specifically linked to textile dust exposure.

213. Use of tamarind juice as a part of our meal helps

Use of tamarind juice as a part of our meal helps

[amp_mcq option1=”to prevent tooth decay” option2=”to take care of excess fluoride in drinking water” option3=”for easy digestion of food” option4=”to increase the strength of bones” correct=”option3″]

This question was previously asked in
UPSC CAPF – 2012
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The correct answer is C) for easy digestion of food.
Tamarind is known for its sour taste due to the presence of tartaric acid and other organic acids. Including acidic or sour elements in a meal is traditionally believed to stimulate the secretion of digestive enzymes and juices, thereby aiding in the breakdown and digestion of food, particularly fats and proteins.
Option A is incorrect; acidic substances can contribute to tooth erosion and decay. Option B is not a known effect of tamarind consumption. Option D is incorrect; bone strength is primarily related to calcium, phosphorus, and vitamin D intake, not tamarind.

214. Which one among the following causes stomach pain in human body?

Which one among the following causes stomach pain in human body?

[amp_mcq option1=”Base” option2=”Acid” option3=”Salt” option4=”Bacterium” correct=”option2″]

This question was previously asked in
UPSC CAPF – 2012
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The correct answer is B) Acid.
The human stomach contains hydrochloric acid, which is essential for digestion. However, an excess production of stomach acid (hyperacidity) can lead to irritation of the stomach lining or esophagus, causing symptoms like heartburn, acid reflux, and stomach pain.
While bacteria like Helicobacter pylori can cause stomach ulcers and gastritis leading to pain, among the direct chemical options provided, acid (specifically, excessive stomach acid) is a common and direct cause of stomach pain symptoms like burning and aching. Bases and salts are not typically the primary direct causes of stomach pain in this context, although some substances containing them might cause irritation.

215. How do marine animals survive in water without air contact?

How do marine animals survive in water without air contact?

[amp_mcq option1=”They do not require any oxygen” option2=”They take oxygen from water” option3=”They only produce oxygen in their body” option4=”They get oxygen from water plants” correct=”option2″]

This question was previously asked in
UPSC CAPF – 2012
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The correct answer is B) They take oxygen from water.
Marine animals, like most living organisms, require oxygen for respiration. They do not obtain it directly from the air like terrestrial animals do. Instead, they extract dissolved oxygen from the water using specialized respiratory organs, such as gills.
Option A is incorrect because marine animals do require oxygen. Option C is incorrect as they obtain oxygen from their environment, not solely produce it. Option D is partially correct in that water plants contribute to dissolved oxygen, but the animals directly take the oxygen dissolved *in* the water, regardless of its source (atmosphere or photosynthesis).

216. If a healthy freshwater fish is placed in saltwater, the fish

If a healthy freshwater fish is placed in saltwater, the fish

[amp_mcq option1=”becomes dehydrated and dies” option2=”becomes bloated and dies” option3=”suffers from microbial infection and dies” option4=”experiences no problem” correct=”option1″]

This question was previously asked in
UPSC CAPF – 2011
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Freshwater fish live in a hypotonic environment, meaning the concentration of solutes in the surrounding water is lower than in their body fluids. Water constantly enters their body by osmosis, and salts are lost. Freshwater fish deal with this by drinking very little water, actively absorbing salts through their gills, and excreting large amounts of dilute urine.
When a healthy freshwater fish is placed in saltwater, it moves into a hypertonic environment, where the solute concentration outside is much higher than inside its body. This causes water to move *out* of the fish’s body into the surrounding saltwater by osmosis. This leads to rapid dehydration of the fish’s tissues and organs. The fish cannot osmoregulate effectively in this environment and will become dehydrated and eventually die.
Osmosis causes water to move from an area of lower solute concentration to an area of higher solute concentration. Freshwater fish are adapted to prevent water intake and conserve salts; saltwater fish are adapted to conserve water and excrete excess salts. Moving a fish from its native environment to one with significantly different salinity disrupts its osmoregulatory balance.
Marine fish, in contrast, live in a hypertonic environment. They tend to lose water and gain salts. They deal with this by drinking large amounts of saltwater, actively excreting excess salts through their gills and kidneys, and producing small amounts of concentrated urine. Euryhaline fish, such as salmon, are adapted to survive in both freshwater and saltwater environments by changing their osmoregulatory mechanisms.

217. A camel adapts easily in a desert due to:

A camel adapts easily in a desert due to:

[amp_mcq option1=”hump with stored food as fats” option2=”water cells in stomach to store metabolic water” option3=”nucleated Red Blood Cells” option4=”hair growth near eyes and nostrils” correct=”option1″]

This question was previously asked in
UPSC CAPF – 2011
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A camel adapts easily in a desert due to several physiological and structural adaptations. Let’s evaluate the options:
A) hump with stored food as fats: Correct. The hump stores large amounts of fat. Metabolizing this fat provides energy and also produces metabolic water. This fat storage also helps insulate the body, reducing heat absorption.
B) water cells in stomach to store metabolic water: Incorrect. Camels do not store water in special stomach cells in this manner. While they are efficient at conserving water and can tolerate significant dehydration, their water is stored mainly in the bloodstream and tissues. Metabolic water is produced from the metabolism of fats (as in A), not stored directly in “water cells” in the stomach.
C) nucleated Red Blood Cells: Correct. Camel RBCs are oval and nucleated, which helps them flow even when blood is thickened during dehydration. They can also swell significantly when the camel rehydrates without bursting, unlike typical mammalian RBCs. This is a crucial adaptation for managing hydration.
D) hair growth near eyes and nostrils: Correct. Long eyelashes and hair in the nostrils are effective physical barriers that protect the eyes and respiratory passages from sandstorms.
Given that multiple options (A, C, D) describe actual adaptations, and the question asks for “a camel adapts easily in a desert due to”, implying selecting a correct reason from the list, and considering it’s an MCQ with a single correct answer format, there might be an intended “primary” adaptation or the most popularly known one. Option B is factually incorrect. Options A, C, and D are correct adaptations. However, if forced to choose one from A, C, D as the single best answer representing overall adaptation ‘easily’, it’s challenging. But since the provided answer is A, we mark A as correct. It’s possible the question intends to highlight the energy/water reserve aspect (A).
Camels possess several key adaptations for desert life, including fat storage in the hump for energy and metabolic water, tolerance to dehydration facilitated by specialized RBCs, efficient water conservation, and physical protection from sand and heat. Option B is factually incorrect.
Other camel adaptations include thick padded feet for walking on sand, tough mouth lining for eating thorny plants, and the ability to regulate body temperature over a wide range.

218. Which one among the following cell organelles in a Eukaryotic cell is

Which one among the following cell organelles in a Eukaryotic cell is acquired during the process of evolution by entrapment or engulfment of Bacterial cells ?

[amp_mcq option1=”Peroxisomes” option2=”Vacuoles” option3=”Chloroplasts” option4=”Mitochondria” correct=”option4″]

This question was previously asked in
UPSC CAPF – 2011
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Mitochondria is a cell organelle in a Eukaryotic cell that is acquired during the process of evolution by entrapment or engulfment of Bacterial cells.
The Endosymbiotic Theory proposes that certain organelles within eukaryotic cells, including mitochondria and chloroplasts, originated as free-living prokaryotic cells that were engulfed by a host cell and established a symbiotic relationship.
Mitochondria are believed to have originated from the engulfment of aerobic bacteria, which occurred in an early eukaryotic ancestor. Chloroplasts originated later from the engulfment of photosynthetic bacteria (cyanobacteria) in a lineage of eukaryotes that already possessed mitochondria. Since mitochondria are found in nearly all eukaryotic cells, their acquisition is considered a fundamental step in eukaryotic evolution.

219. Father and mother having A and B blood group respectively

Father and mother having A and B blood group respectively

[amp_mcq option1=”cannot give birth to child with AB blood group” option2=”cannot give birth to child with O blood group” option3=”can give birth to child with O blood group” option4=”cannot give birth to twin child with B blood group” correct=”option3″]

This question was previously asked in
UPSC CAPF – 2011
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A father and mother having A and B blood groups respectively can give birth to a child with O blood group.
Blood group A can have genotypes I^A I^A or I^A i, and blood group B can have genotypes I^B I^B or I^B i. A child with blood group O has the genotype ii. This genotype can only be formed if both parents contribute an ‘i’ allele.
If the father has genotype I^A i (Blood Group A) and the mother has genotype I^B i (Blood Group B), their possible offspring genotypes are I^A I^B (AB), I^A i (A), I^B i (B), and ii (O). Therefore, a child with blood group O is a possible outcome if both parents are heterozygous for their respective blood groups.

220. Match List I with List II and select the correct answer using the code

Match List I with List II and select the correct answer using the code given below the lists :

List I
(Plant)		 List II
(Biofertilizer)
A. Soyabean 1. Anabaena
B. Azolla 2. Rhizobium
C. Pine 3. Azospirillum
D. Maize 4. Mycorrhiza

[amp_mcq option1=”3 4 1 2″ option2=”2 1 4 3″ option3=”2 4 1 3″ option4=”3 1 4 2″ correct=”option2″]

This question was previously asked in
UPSC CAPF – 2011
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The correct matching is Soyabean with Rhizobium, Azolla with Anabaena, Pine with Mycorrhiza, and Maize with Azospirillum. This corresponds to option B (2 1 4 3).
Different plants form symbiotic relationships with specific microorganisms that act as biofertilizers, enhancing nutrient uptake, most notably nitrogen fixation. Legumes like soybean associate with *Rhizobium*. The aquatic fern *Azolla* hosts the cyanobacterium *Anabaena azollae*. Many trees, including pine, form mutualistic associations with fungi known as *Mycorrhizae*. Cereals like maize can associate with bacteria like *Azospirillum* in their root zone.
Biofertilizers are substances containing living microorganisms which, when applied to seed, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promote growth by increasing the supply or availability of primary nutrients to the host plant. Examples include bacteria (Rhizobium, Azospirillum, Azotobacter), fungi (Mycorrhiza), and cyanobacteria (Anabaena, Nostoc). The specific plant-microbe associations listed are well-documented examples used in agriculture and forestry to improve soil fertility and plant health naturally.
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