Skip to content
GK24

SSC 2023 Previous Year GK Questions with Answers

GK questions asked in SSC 2023, with answers and explanations.

Previous Year Questions

Q61.Indian HistoryAsked in: SSC GD Constable · 13 Jan 2023, Shift 4Medium

The tribal group called 'Santhals' rose in revolt in _______.

  1. A.1876
  2. B.1855
  3. C.1896
  4. D.1860
Show answer

Correct answer: B. 1855

Explanation

The correct answer is B, 1855. The Santhal rebellion, known as the Hul, broke out on 30 June 1855 in the Rajmahal hills of the Santhal Parganas, in what is now Jharkhand. It was led by the brothers Sidhu and Kanhu Murmu, along with Chand and Bhairav, who gathered thousands of Santhals against the moneylenders, traders, zamindars and Company officials who had taken over their land and pushed them into bonded labour. The rising was put down with heavy force by 1856, but it forced the British to carve out a separate Santhal Parganas district with special rules barring outsiders from buying tribal land. Option A is wrong because no Santhal rising took place in 1876. Option C is wrong because 1896 is close to but not the year of the Munda ulgulan of Birsa Munda, which began in 1899. Option D is wrong because by 1860 the rebellion had already been crushed. Exam tip: Santhal Hul 1855 under Sidhu and Kanhu; Munda Ulgulan 1899 to 1900 under Birsa Munda.

Q62.Indian HistoryAsked in: SSC GD Constable · 30 Jan 2023, Shift 4Easy

Why was the year 1757 an important year for the English East India Company in India?

  1. A.In 1757 the English East India Company got control over Hyderabad by defeating the Nizam in the Battle of Plassey.
  2. B.In 1757 the English East India Company got control over Madras by defeating Nawab Siraj-ud-daulah in the Battle of Plassey.
  3. C.In 1757 the English East India Company got control over Oudh by defeating Nawab Siraj-ud-daulah in the Battle of Berar.
  4. D.In 1757 the English East India Company got control over Bengal by defeating Nawab Siraj-ud-daulah in the Battle of Plassey.
Show answer

Correct answer: D. In 1757 the English East India Company got control over Bengal by defeating Nawab Siraj-ud-daulah in the Battle of Plassey.

Explanation

The correct answer is D. The Battle of Plassey was fought on 23 June 1757 on the bank of the Bhagirathi near Palashi in Bengal, and Robert Clive's small Company force defeated Nawab Siraj-ud-daulah there. The victory owed less to fighting than to treachery: the Nawab's commander Mir Jafar kept his troops out of the battle after a secret bargain, and the bankers of Murshidabad backed the plot. Mir Jafar was made Nawab, and the Company won a hold over the trade and revenue of Bengal, which is why 1757 is treated as the start of British political power in India. Option A is wrong because the Nizam of Hyderabad was not a party to Plassey. Option B is wrong because Madras was already a Company settlement and Plassey was fought in Bengal. Option C is wrong because there was no Battle of Berar, and Oudh came under Company influence later. Exam tip: Plassey 1757 against Siraj-ud-daulah, Buxar 1764 against Mir Qasim, Shuja-ud-daula and Shah Alam II.

Q63.Indian EconomyAsked in: SSC GD Constable · 10 Jan 2023, Shift 2Medium

Rs. 50 banknote of Mahatma Gandhi (New) series has base colour of ______.

  1. A.chocolate brown
  2. B.stone grey
  3. C.fluorescent blue
  4. D.lavender
Show answer

Correct answer: C. fluorescent blue

Explanation

The correct answer is C, fluorescent blue. The Reserve Bank of India issued the fifty-rupee note of the Mahatma Gandhi (New) series in August 2017 with fluorescent blue as its base colour. Its reverse carries the stone chariot of the Vittala temple at Hampi in Karnataka, a World Heritage site, and the note measures 66 mm by 135 mm. Every note of this series pairs one colour with one monument, which is the way paper setters like to test it. Option A is wrong because chocolate brown is the base colour of the ten-rupee note, whose reverse shows the Konark Sun Temple. Option B is wrong because stone grey belongs to the five-hundred-rupee note, which carries the Red Fort. Option D is wrong because lavender is the colour of the hundred-rupee note, whose reverse shows Rani ki Vav in Gujarat. Exam tip: 10 chocolate brown with Konark, 20 greenish yellow with Ellora, 50 fluorescent blue with Hampi, 100 lavender with Rani ki Vav, 200 bright yellow with Sanchi, 500 stone grey with the Red Fort.

Q64.GeographyAsked in: SSC GD Constable · 12 Jan 2023, Shift 3Easy

Which of the following is NOT a sedimentary rock?

  1. A.Granite
  2. B.Sand stone
  3. C.Loess
  4. D.Shale
Show answer

Correct answer: A. Granite

Explanation

The correct answer is A, Granite. Granite is an igneous rock, not a sedimentary one. It forms when magma cools slowly deep inside the crust, so its crystals of quartz, feldspar and mica are large enough to see; because it cooled below the surface it is called an intrusive or plutonic rock. Sedimentary rocks are different: they are built up in layers from sediment that water, wind or ice deposits and then compacts and cements. Option B is wrong because sandstone is sedimentary, made of cemented sand grains. Option C is wrong because loess is sedimentary too, a fine silt carried and dropped by wind, and it makes the fertile soil of northern China. Option D is wrong because shale is sedimentary, formed from compressed clay and mud. Granite turns into the metamorphic rock gneiss under heat and pressure. Exam tip: granite and basalt igneous; sandstone, shale, limestone and loess sedimentary; marble, gneiss, slate and quartzite metamorphic.

Q65.Indian PolityAsked in: SSC GD Constable · 16 Jan 2023, Shift 2Easy

Which of the following Articles of the Indian Constitution deals with the Right against Exploitation?

  1. A.Article 33 - 34
  2. B.Article 37 - 38
  3. C.Article 23 - 24
  4. D.Article 27 - 28
Show answer

Correct answer: C. Article 23 - 24

Explanation

The correct answer is C, Article 23 - 24. The Right against Exploitation is given by Articles 23 and 24 in Part III of the Constitution. Article 23 forbids traffic in human beings, begar and other forms of forced labour, and lets the State impose compulsory service for a public purpose without discrimination. Article 24 forbids the employment of a child below fourteen years in any factory, mine or other hazardous work. Article 23 led to the Bonded Labour System (Abolition) Act, 1976 and Article 24 to the child labour laws. Option A is wrong because Article 33 lets Parliament restrict the rights of the armed forces and Article 34 covers martial law. Option B is wrong because Articles 37 and 38 are in Part IV, the Directive Principles, and are not enforceable in court. Option D is wrong because Articles 27 and 28 belong to the Right to Freedom of Religion. Exam tip: 14-18 equality, 19-22 freedom, 23-24 exploitation, 25-28 religion, 29-30 cultural and educational rights.

Q66.Indian EconomyAsked in: SSC MTS · 03 May 2023, Shift 2Medium

When the British rule ended in India in the year 1947 the literacy rate was just _____.

  1. A.22 percent
  2. B.12 percent
  3. C.20 percent
  4. D.18 percent
Show answer

Correct answer: B. 12 percent

Explanation

The correct answer is B, 12 percent. India's literacy rate at independence in 1947 is put at about 12 per cent.

Colonial education reached only a thin urban layer, and the figure for women was far lower, around six per cent. The first census after independence, in 1951, recorded 18.33 per cent literacy, and the number has climbed steadily since: 28.3 per cent in 1961, 52.2 per cent in 1991 and 74.04 per cent in the census of 2011. Kerala has long stood first among the states and Bihar last. A person aged seven years or above who can read and write with understanding is counted as literate.

Options A, C and D are wrong. Twenty and twenty-two per cent are higher than any figure recorded in that decade, and 18 per cent is the 1951 census reading, not the 1947 one, which is the usual trap in this question.

Exam tip: 1947 about 12 per cent, 1951 census 18.33 per cent, 2011 census 74.04 per cent.

Q67.Art & CultureAsked in: SSC MTS · 03 May 2023, Shift 2Medium

Bahmani Monuments at Gulbarga, Karnataka represent ________ style of architecture.

  1. A.Deccan
  2. B.Mameluke
  3. C.Sikh
  4. D.Nagara
Show answer

Correct answer: A. Deccan

Explanation

The correct answer is A, Deccan. The Bahmani buildings at Gulbarga belong to the Deccan or Provincial style of Indo-Islamic architecture.

When the Bahmani sultanate broke away from Delhi in 1347 it developed its own manner, blending Persian and Turkish ideas brought by architects from Iran with local craft and stone. The Jama Masjid inside Gulbarga fort is its finest example: it has no open courtyard, and sixty-three domes and wide arches cover the whole prayer hall, which is unusual in India. The Haft Gumbaz tombs stand nearby. After the capital moved to Bidar the same style produced the Mahmud Gawan madrasa.

Option B, Mameluke or Slave dynasty style, belongs to the early Delhi Sultanate, as in the Qutub Minar. Option C, Sikh style, is seen in gurdwaras of Punjab from a much later period. Option D, Nagara, is a north Indian temple style with a curved shikhara.

Exam tip: Delhi styles are Imperial, regional ones Provincial; Gulbarga and Bidar - Deccan style.

Q68.Sports GKAsked in: SSC MTS · 15 May, 2023, Shift 2Easy

Cricket World Cup, 1983 was held in which of the following places?

  1. A.England
  2. B.Australia
  3. C.West Indies
  4. D.India
Show answer

Correct answer: A. England

Explanation

The correct answer is A, England. The 1983 Cricket World Cup was hosted by England, and the final was played at Lord's in London.

India, led by Kapil Dev, beat the West Indies by 43 runs in that final on 25 June 1983, scoring only 183 and then bowling the holders out for 140. Mohinder Amarnath was Man of the Match. It was India's first World Cup title and the turning point that made one-day cricket a mass game in the country. England also hosted the first three editions, in 1975, 1979 and 1983, all played in white clothing with a red ball over sixty overs a side.

Option B is wrong because Australia first co-hosted in 1992, with New Zealand. Option C is wrong as the West Indies hosted in 2007. Option D is wrong because India first co-hosted in 1987.

Exam tip: 1975, 1979, 1983 in England; India won 1983 and 2011.

Q69.Indian HistoryAsked in: SSC CGL · 27 Jul 2023, Shift 3Medium

Name the Bhakti Saint from South India who was initially a Jaina and a minister in the court of a Chalukya king in the twelfth century.

  1. A.Karaikkal Ammaiyar
  2. B.Basavanna
  3. C.Eknath
  4. D.Tallapaka Annamacharya
Show answer

Correct answer: B. Basavanna

Explanation

The correct answer is B, Basavanna. He was a Jaina in his early life and served as a minister in a Chalukya court in the twelfth century.

Basavanna, also called Basaveshwara, led the Virashaiva or Lingayat movement in Karnataka. His followers worship Shiva in the form of a linga, reject caste distinctions, temple ritual and Brahmanical authority, and do not believe in rebirth. He composed his teachings as vachanas, short prose-poems in Kannada, and the movement ran an assembly called the Anubhava Mantapa where men and women debated freely. Allama Prabhu and Akka Mahadevi were among the other leading figures of the movement.

A is wrong: Karaikkal Ammaiyar was a Tamil Nayanar saint of a much earlier period. C is wrong: Eknath was a Marathi Varkari saint of the sixteenth century. D is wrong: Tallapaka Annamacharya was a Telugu composer of devotional songs at Tirupati.

Exam tip: Basavanna - twelfth century, Karnataka, Lingayat or Virashaiva movement, vachanas in Kannada.

Q70.Indian HistoryAsked in: SSC CGL · 19 Jul 2023, Shift 1Hard

Imadshahi family was known for the foundation of which state?

  1. A.Berar
  2. B.Bidar
  3. C.Ahmednagar
  4. D.Golkonda
Show answer

Correct answer: A. Berar

Explanation

The correct answer is A, Berar. The Imad Shahi dynasty founded the Sultanate of Berar in 1490.

As the Bahmani kingdom of the Deccan broke up in the late fifteenth century, five successor sultanates appeared. Fathullah Imad-ul-Mulk, the Bahmani governor of Berar, declared independence in 1490 and started the Imad Shahi line with Gawilgarh and Ellichpur as its centres. Berar was the smallest and weakest of the five and was annexed by Ahmednagar in 1574, and later passed to the Mughals under Akbar.

B is wrong: Bidar was ruled by the Barid Shahi dynasty. C is wrong: Ahmednagar was founded by Malik Ahmad of the Nizam Shahi dynasty. D is wrong: Golkonda was the seat of the Qutb Shahi dynasty founded by Quli Qutb Shah.

Exam tip: Five Deccan sultanates - Adil Shahi in Bijapur, Qutb Shahi in Golconda, Nizam Shahi in Ahmednagar, Imad Shahi in Berar, Barid Shahi in Bidar.

Q71.Indian HistoryAsked in: SSC CGL · 18 Jul 2023, Shift 1Medium

In which year was the Vernacular Press Act enacted in British India?

  1. A.1876
  2. B.1874
  3. C.1872
  4. D.1878
Show answer

Correct answer: D. 1878

Explanation

The correct answer is D, 1878. The Vernacular Press Act was passed in 1878, when Lord Lytton was Viceroy of India.

The Act was aimed at Indian-language newspapers, which had grown sharply critical of British rule after the famine of 1876-78. It allowed a magistrate to demand a bond from a printer or publisher, and to seize the press if seditious matter appeared. Because English papers were left untouched, it was nicknamed the 'Gagging Act'. Surendranath Banerjea and others protested strongly, and the Amrita Bazar Patrika switched overnight from Bengali to English to escape it. Lord Ripon repealed the Act in 1882.

A is wrong: 1876 is the year of the Royal Titles Act, which made Queen Victoria Empress of India. B is wrong: no press law was passed in 1874. C is wrong: 1872 saw the first non-synchronous all-India census, not a press law.

Exam tip: Vernacular Press Act - passed by Lytton in 1878, repealed by Ripon in 1882.

Q72.Indian PolityAsked in: SSC CGL · 17 Jul 2023, Shift 4Easy

The Fundamental Duties of citizens were added to the Constitution of India, upon the recommendations of which of the following committees?

  1. A.Raja Chelliah Committee
  2. B.Santhanam Committee
  3. C.Kelkar Committee
  4. D.Swaran Singh Committee
Show answer

Correct answer: D. Swaran Singh Committee

Explanation

The correct answer is D, Swaran Singh Committee. The Fundamental Duties were added on the recommendation of this committee, set up in 1976.

The Swaran Singh Committee suggested that the Constitution should spell out the duties of citizens alongside their rights. Acting on it, the 42nd Constitutional Amendment Act, 1976 inserted Part IVA with a single article, Article 51A, listing ten Fundamental Duties. An eleventh duty, that a parent or guardian should provide education to a child between six and fourteen years, was added by the 86th Amendment Act, 2002. The duties are not by themselves enforceable in a court.

A is wrong: the Raja Chelliah Committee reported on tax reforms in the early 1990s. B is wrong: the Santhanam Committee of 1962 dealt with prevention of corruption and led to the Central Vigilance Commission. C is wrong: the Kelkar Committee also worked on direct and indirect tax reform.

Exam tip: Swaran Singh Committee to 42nd Amendment, 1976 to Part IVA, Article 51A, ten duties; the eleventh came in 2002.

Q73.Indian PolityAsked in: SSC CGL · 26 Jul 2023, Shift 4Medium

What is the duty of the Chief Minister, as mentioned under Article 167 of the Indian Constitution?

  1. A.Communication of all decisions of the Council of Ministers to the Governor.
  2. B.Appointment and removal of Council of the Ministers.
  3. C.Appointment of the Speaker of the Legislative Assembly.
  4. D.Appointment of Advocate General of the state in consultation with Attorney general.
Show answer

Correct answer: A. Communication of all decisions of the Council of Ministers to the Governor.

Explanation

The correct answer is A, Communication of all decisions of the Council of Ministers to the Governor. Article 167 lists the duties of the Chief Minister towards the Governor.

Under Article 167 the Chief Minister must communicate to the Governor every decision of the Council of Ministers about the administration of the state and about proposals for legislation, must furnish any information on these matters that the Governor calls for, and must place before the Council any matter on which a single Minister has taken a decision but the Council has not considered. It is the state counterpart of Article 78, which lays down the same duties for the Prime Minister towards the President.

B is wrong: Ministers are appointed and removed by the Governor under Article 164, on the Chief Minister's advice. C is wrong: the Speaker is elected by the members of the Legislative Assembly under Article 178. D is wrong: the Advocate General is appointed by the Governor under Article 165.

Exam tip: Article 78 - Prime Minister's duties; Article 167 - Chief Minister's duties.

Q74.Computer AwarenessAsked in: SSC CHSL · 16 March, 2023, Shift 3Medium

Which of the following shortcut key is used to make the contents of a cell italic in MS-Excel 365 ?

  1. A.Ctrl + 4
  2. B.Ctrl + 3
  3. C.Ctrl + 6
  4. D.Ctrl + 2
Show answer

Correct answer: B. Ctrl + 3

Explanation

The correct answer is B, Ctrl + 3. Pressing Ctrl + 3 turns the contents of the selected cell or range italic in Microsoft Excel, and pressing it again removes the italics; Ctrl + I does exactly the same job. Excel keeps a whole set of number-key shortcuts for formatting, which is worth learning as a block: Ctrl + 1 opens the Format Cells dialog box, Ctrl + 2 applies or removes bold, Ctrl + 4 underlines, Ctrl + 5 strikes a line through the text, Ctrl + 8 shows or hides outline symbols and Ctrl + 9 hides the selected rows. Option A is wrong because Ctrl + 4 applies underline, not italics. Option D is wrong because Ctrl + 2 applies bold. Option C is wrong because Ctrl + 6 switches the display of objects on the sheet on and off. Exam tip: in Excel remember the run Ctrl + 1 Format Cells, Ctrl + 2 bold, Ctrl + 3 italic, Ctrl + 4 underline and Ctrl + 5 strikethrough.

Q75.GeographyAsked in: SSC CHSL · 17 March, 2023, Shift 2Easy

Which among the following lakes lies on the borders of Andhra Pradesh and Tamil Nadu?

  1. A.Dal
  2. B.Pulicat
  3. C.Loktak
  4. D.Sambhar
Show answer

Correct answer: B. Pulicat

Explanation

The correct answer is B, Pulicat. Pulicat Lake lies across the boundary of Andhra Pradesh and Tamil Nadu, with the larger share in Andhra Pradesh, and is the second largest brackish-water lagoon in India after Chilika. A long barrier island, Sriharikota, separates it from the Bay of Bengal, and that island holds the Satish Dhawan Space Centre from which ISRO launches its rockets. The lagoon is fed by the Arani, Kalangi and Swarnamukhi rivers and the Pulicat Bird Sanctuary on its shores draws flamingoes and pelicans. Option A is wrong because Dal is a freshwater lake in Srinagar, Jammu and Kashmir. Option C is wrong because Loktak, with its floating phumdis and the Keibul Lamjao National Park, is in Manipur. Option D is wrong because Sambhar, India's largest inland salt lake, lies in Rajasthan. Exam tip: Chilika in Odisha is India's largest brackish lagoon and Pulicat the second, with Sriharikota on it.

Q76.Indian PolityAsked in: SSC CHSL · 09 March, 2023, Shift 4Easy

Which of the following comes under the part IX of the Indian constitution?

  1. A.Relations between the Union and the States
  2. B.The Scheduled and Tribal Areas
  3. C.The Panchayats
  4. D.Finance, Property, Contracts and Suits
Show answer

Correct answer: C. The Panchayats

Explanation

The correct answer is C, The Panchayats. Part IX of the Constitution of India is headed 'The Panchayats'. It was inserted by the 73rd Constitutional Amendment Act, 1992, which came into force on 24 April 1993, now marked as National Panchayati Raj Day, and it runs from Article 243 to Article 243-O. Part IX gives panchayats a three-tier structure at village, intermediate and district level, a fixed term of five years, reservation of seats for Scheduled Castes, Scheduled Tribes and women, a State Election Commission to hold their elections and a State Finance Commission to review their funds; the Eleventh Schedule lists the subjects handed to them. Option A is wrong because relations between the Union and the States form Part XI. Option B is wrong because the Scheduled and Tribal Areas are in Part X, read with the Fifth and Sixth Schedules. Option D is wrong because finance, property, contracts and suits make up Part XII. Exam tip: Part IX Panchayats with the Eleventh Schedule, Part IX-A Municipalities with the Twelfth.

Q77.GeographyAsked in: SSC CHSL · 16 March, 2023, Shift 2Easy

When are the kharif crops harvested?

  1. A.July - August
  2. B.September - October
  3. C.March - April
  4. D.January - February
Show answer

Correct answer: B. September - October

Explanation

The correct answer is B, September - October. Kharif crops are the monsoon crops: they are sown with the onset of the south-west monsoon in June and July and harvested in September and October, when the rains withdraw. They need heat and plenty of water, and the group includes rice, maize, jowar, bajra, ragi, arhar, moong, urad, cotton, jute, groundnut and soybean. The rabi season follows, with sowing from October to December and harvesting in March and April — wheat, barley, gram, peas, mustard and linseed. Between the two comes the short zaid season from March to June, which gives watermelon, muskmelon, cucumber and fodder crops. Option A is wrong because July and August are the growing months of the kharif crop, not the harvest. Option C is wrong because March and April are when rabi crops are cut. Option D is wrong because January and February fall in the middle of the rabi season. Exam tip: kharif sown June-July and cut September-October; rabi sown October-December and cut March-April.

Q78.Indian PolityAsked in: SSC CHSL · 14 March, 2023, Shift 2Medium

Concurrent list of seventh schedule does NOT have provision related to ______.

  1. A.Industrial and labour disputes
  2. B.Forests
  3. C.Taxes on lands and buildings
  4. D.Economic and social planning
Show answer

Correct answer: C. Taxes on lands and buildings

Explanation

The correct answer is C, Taxes on lands and buildings. Taxes on lands and buildings is entry 49 of the State List, so it is not in the Concurrent List. The Seventh Schedule divides law-making power into three lists: the Union List for Parliament alone, the State List for the state legislatures, and the Concurrent List on which both may legislate, with the Union law prevailing in a clash under Article 254. Option B is wrong because forests is in the Concurrent List — it was moved there from the State List by the 42nd Amendment Act, 1976, along with education, weights and measures, administration of justice and the protection of wild animals and birds. Option A is wrong because industrial and labour disputes is entry 22 of the Concurrent List. Option D is wrong because economic and social planning is entry 20 of the same list. Exam tip: taxation entries sit almost entirely in the Union or State List; stamp duties is the one notable tax entry in the Concurrent List.

Q79.Computer AwarenessAsked in: SSC CHSL · 15 March, 2023, Shift 3Easy

Preet wants to use object-oriented programming language for her application. Which among the following languages should she pick?

  1. A.Either Java or Pascal
  2. B.Pascal
  3. C.BASIC
  4. D.Java
Show answer

Correct answer: D. Java

Explanation

The correct answer is D, Java. Java is an object-oriented programming language, so it is the right pick for Preet. It was created by James Gosling at Sun Microsystems and released in 1995; every piece of code sits inside a class, and the language is built on the four pillars of object orientation — encapsulation, inheritance, polymorphism and abstraction. Java source is compiled into bytecode that any Java Virtual Machine can run, which is why it is described as write once, run anywhere. Option B is wrong because Pascal, written by Niklaus Wirth in 1970 for teaching, is a structured procedural language; only the later Object Pascal added classes. Option A is wrong for the same reason, since it offers Pascal as an equal choice. Option C is wrong because BASIC, made by Kemeny and Kurtz in 1964, is a simple procedural language for beginners. Exam tip: C++, Java, Python, C# and Smalltalk are object-oriented, while C, Pascal, FORTRAN, COBOL and BASIC are procedural.

Q80.Computer AwarenessAsked in: SSC CHSL · 02 Nov, 2023, Shift 1Medium

Which of the following types of firewall operates at the Network layer to examine incoming and outgoing packets?

  1. A.Circuit-level gateway
  2. B.Application-level gateway
  3. C.Packet filtering
  4. D.Network filtering
Show answer

Correct answer: C. Packet filtering

Explanation

The correct answer is C, Packet filtering. A packet filtering firewall works at the network layer, the third layer of the OSI model, where it reads the header of every incoming and outgoing packet and compares the source and destination IP address, the port number and the protocol against a list of rules, then allows the packet through or drops it. It is the oldest and fastest kind of firewall and needs little memory, but it is stateless: it judges each packet on its own and cannot look inside the data, so it misses attacks hidden in the payload. Option A is wrong because a circuit-level gateway works at the session layer and only checks that the TCP handshake is valid. Option B is wrong because an application-level gateway, or proxy firewall, works at the application layer and understands protocols such as HTTP and FTP. Option D is wrong because network filtering is not a recognised firewall type. Exam tip: packet filter at the network layer, circuit-level at the session layer, proxy at the application layer.