HCS 2020: Biology MCQ Series Part-IV
Baljit Dhaka

HCS 2020: Biology MCQ Series Part-IV

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Multiple Choice Questions For HCS 2020 Exam: BIOLOGY PART-IV

Haryana Civil Services Exam 2020

Important 20000 MCQ Series For HCS 2020 Exam: BIOLOGY PART-IV

Q1. Bile is stored in the

(a) Gall-bladder

(b) Duodenum

(c) Liver

(d) Spleen

Ans. (a)

Explanation: Bile, or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile) and stored and concentrated in the gallbladder.

Q2. The saliva secreted in the mouth digests

(a) Proteins

(b) Starch

(c) Fats

(d) Vitamins

Ans. (b)

Explanation: The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.

Q3. Which of the following weeds has been found useful to check water pollution caused by industrial effluents?

(a) Parthenium

(b) Elephant grass

(c) Water hyacinth

(d) Both (a) and (b)

Ans. (c)

Explanation: Water hyacinth as indicator of heavy metal pollution in the tropics. The water hyacinth (Eichhornia crassipes) is a common aquatic plant in many tropical countries. Its ability absorb nutrients and other elements from the water has made it possible to use it for water purification purposes.

Q4. Which of the following does not cause pollution ?

(a) Burning of petrol

(b) Use of Ansar energy

(c) Burning of rubber

(d) All of the above

Ans. (b)

Explanation: Ansar power is pollution free and causes no greenhouse gases to be emitted after installation. Reduced dependence on foreign oil and fossil fuels. Renewable clean power that is available every day of the year, even cloudy days produce some power.

Q5. Excess amount of absorbed water by plants is liberated out by :

(a) Evaporation

(b) Osmosis

(c) Diffusion

(d) Transpiration

Ans. (d)

Explanation: Water vapour transpires constantly through pores (stomata) in the surface of plant’s leaves. Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth and metabolism.

Q6. What is a sponge?

(a) a fossil

(b) a plant

(c) an animal

(d) a fungus

Ans. (c)

Explanation: Sponges, the members of the phylum Porifera  Kingdom- Animalia

Q7. Types of vertebrate animals which creep and crawl are called :

(a) mammalians

(b) amphibians

(c) mollusks

(d) reptilians

Ans. (d)

Explanation: The class name refers to their creeping or crawling mode of locomotion. They are mostly terrestrial animals and their body is covered by dry and cornified skin, epidermal scales or scutes. Heart is usually three-chambered, but four-chambered in crocodiles. Snakes and lizards shed their scales as skin cast. They are oviparous and development is direct. 

Examples: Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator). Hemidactylus (Wall lizard), Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper). 

Q8. Which of the following enzymes aids in coagulation of blood?

(a) Tryptase 

(b) Pepsin

(c) Rennin 

(d) Amylase

Ans. (b)

Explanation: Pepsin enzymes aids in coagulation of blood.

Q9. Bio - diesel is mostly produced by:

(a) Myrtaceae

(b) Malvaceae

(c) Liliaceae

(d) Euphorbiaceae

Ans. (d)

Explanation: Bio-diesel is mostly produced by Jatropha which is a genus of flowering plants in the spurge family, Euphorbiaceae.

Q10. Flowerless plants are termed as:

(a) Phanerogams

(b) Bryophytes

(c) Thallophytes

(d) Cryptogams

Ans. (d)


Phanerogams: Any plant that produces seeds

Cryptogams: A cryptogam is a plant that reproduces by spores, without flowers or seeds. "Cryptogamae" means hidden reproduction, referring to the fact that no seed is produced, thus cryptogams represent the non-seed bearing plants.

Q11. Substances which are used to bring down the temperature in high fever condition are called :

(a) Antiseptics

(b) Pyretics

(c) Antipyretics

(d) Antibiotics

Ans. (c)

Explanation: An antipyretic (from anti- 'against' and pyretic 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which results in a reduction in fever.

Q12. Birds usually have a single

(a) Kidney

(b) Lung

(c) Testis

(d) Ovary

Ans. (d)

Explanation: Male birds have two testes that produce sperm, and most female birds usually have only one ovary that produces eggs. A bird's testes or ovary greatly increase in size during the breeding season.

Q13. Alfalfa is the name of a kind of

(a) Forest

(b) Crop

(c) Grass

(d) None of these

Ans. (b)

Explanation: Alfalfa also called lucerne and called Medicago sativa in binomial nomenclature, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop.

Q14. Which cells in our body have the least regenerative power?

(a) Brain cells

(b) Muscle cells

(c) Bone cells

(d) Liver cells

Ans. (d)

Explanation: Most of our body cells are replaced regularly. Skin follicles, hair, nails are examples. But the organ with maximum regeneration capacity is liver.

Q15. Which one of the following pairs is correctly matched ?

(a) Tetanus- BCG

(b) Tuberculosis –ATS

(c) Malaria – Chloroquine

(d) Scurvy -Thiamine

Ans. (c)

Explanation: Tuberculosis- BCG vaccine It is the live attenuated form of Mycobacterium bovis related to Mycobacterium tuberculosis, the bacterium which causes tuberculosis in humans. 

Tetanus- Anti Tetanus Serum (ATS) It is a medication made up of antibodies against the tetanus toxin. It is used to prevent tetanus in those who have a wound that is at high risk and have not been fully vaccinated with tetanus toxoid.

Chloroquine is a medication primarily used to prevent and treat malaria in areas where malaria remains sensitive to its effects.

Scurvy is a disease resulting from a lack of vitamin C (ascorbic acid). Early symptoms of deficiency include weakness, feeling tired and sore arms and legs. Without treatment, decreased red blood cells, gum disease, changes to hair, and bleeding from the skin may occur.

Q16. The carbon dioxide content in the air that we exhale is about

(a) 4%

(b) 8%

(c) 12%  

(d) 16%

Ans. (a)

Explanation: The amount of inhaled air contains 21% of oxygen and 0.04% of carbon dioxide, while the air we breathe out contains 16.4% of oxygen and 4.4% of carbon dioxide. This is because our cells use oxygen from the inhaled air to release energy and give out carbon dioxide as a byproduct.

Q17. Blood pressure is controlled by

(a) Adrenal gland

(b) Thyroid gland

(c) Thymus

(d) Corpus luteum

Ans. (a)

Explanation: The kidneys provide a hormonal mechanism for the regulation of blood pressure by managing blood volume. The renin‐angiotensin‐aldosterone system of the kidneys regulates blood volume. In response to rising blood pressure, the juxtaglomerular cells in the kidneys secrete renin into the blood.

Q18. The total number of ear bones is

(a) 2

(b) 4

(c) 3

(d) 8

Ans. (c) 

Explanation: Ear bone, also called Auditory Ossicle, any of the three tiny bones in the middle ear of all mammals. These are the malleus, or hammer, the incus, or anvil, and the stapes, or stirrup.

Q19. Which one of the following is the most sensitive Indicator of the  health of a community?

(a) Birth rate

(b) Infant mortality rate

(c) Death rate

(d) Maternal mortality rate

Ans. (b)

Explanation: Infant mortality rate (IMR) is the number of deaths per 1,000 live births of children under one year of age. The rate for a given region is the number of children dying under one year of age, divided by the number of live births during the year, multiplied by 1,000.

Q20. Bakeries use yeast in bread making because it

(a) makes the bread hard

(b) makes the bread soft and spongy

(c) enhances the food values

(d) keeps the bread fresh

Ans. (b)

Explanation: Baker's yeast is the common name for the strains of yeast commonly used in baking bread and bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ethanol.

Q21. “Pace-maker" is associated with

(a) Kidney

(b) Brain

(c) Heart

(d) Lung

Ans. (c)

Explanation: The SA node is the heart's natural pacemaker. The SA node consists of a cluster of cells that are situated in the upper part of the wall of the right atrium (the right upper chamber of the heart). The electrical impulses are generated there. The SA node is also called the sinus node.

Q22. Halophytes are plants that can grow in soil having a high content of______

(a) Salt

(b) Humus   

(c) water

(d) All of the above

Ans. (a)

Explanation: A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores.

Q23. The largest flightless bird which can run at a great speed is

(a) Penguin

(b) Kiwi

(c) Ostrich

(d) Emu

Ans. (c)

Explanation: The Ostrich is the largest living species of bird. They usually weigh from 63 to 145 kilograms. Although it cannot fly, the ostrich is also the fastest-running bird today; it can run up to about 70 kilometres in an hour.

Q24. Human beings have two ears because two ears help

(a) to judge the direction of sound

(b) to hear even a feeble sound

(c) to enjoy music better

(d) to distinguish between two kinds of sounds arriving at the ears in opposite directions

Ans. (d)

Explanation: We have two ears basically to widen the scope of hearing so that we can find out where sounds are coming from, and from what distance; i.e., sound localization. The brain utilizes subtle differences in intensity, spectral, and timing cues to allow us to localize sound sources

Q25. The vitamin which cannot be had from any vegetables is

(a) Vitamin B

(b) Vitamin C

(c) Vitamin D

(d) Vitamin E

Ans. (c)

Explanation: A human body produces vitamin D as a response to sun exposure. A person can also boost their vitamin D intake through certain foods or supplements.

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