AP Computer Science Principles Theory & Concepts Exam With
Correct Answers Version 2026/2027
Question 1
An internet service provider (ISP) is upgrading a city’s network infrastructure. The engineers are
choosing between a hierarchical routing architecture and a fully mesh-connected network
architecture. Explain how the internet utilizes redundant routing to ensure fault tolerance. Describe
what happens to data packets when a primary router or physical fiber-optic cable is suddenly
severed during data transmission.
Correct Answer: The internet is designed as a distributed, redundant network where multiple paths
exist between any two points. This redundancy establishes fault tolerance, meaning the network can
continue to function properly even when individual components fail. Data is broken down into small
units called packets, each containing routing metadata (such as sender and receiver IP addresses).
Routers constantly evaluate network traffic and topology dynamically using routing protocols. If a
primary router or physical cable is severed, the surrounding routers automatically detect the loss of
connection and re-route the remaining packets along alternative paths. Packets may arrive out of
order or via different routes, but the receiving device reassembles them into the original file using
transmission protocols (TCP).
Question 2
A software development team is designing an online multiplayer game. They need to choose
between using the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) for
different components of the application. Contrast the operational mechanisms of TCP and UDP.
Explain which protocol is best suited for loading the player's account inventory data, and which
protocol is best suited for transmitting real-time player position coordinates during a match.
Correct Answer: TCP is a connection-oriented, reliable protocol that guarantees all packets arrive in
order and without errors by using a "three-way handshake" to establish a connection, tracking
packet sequence numbers, and requiring the receiver to acknowledge receipt. If a packet is lost, TCP
triggers a retransmission. UDP is a connectionless, lightweight protocol that sends packets
(datagrams) continuously without establishing a formal connection, tracking order, or checking for
delivery verification. For loading inventory data, TCP is mandatory because every single item asset
must load without error; missing data would corrupt the inventory state. For real-time player
position coordinates, UDP is ideal because speed and low latency are prioritized over absolute
reliability; if a position packet is dropped, it is immediately made obsolete by a newer position packet
a fraction of a second later.
Question 3
The digital divide remains a significant challenge for global technology equity. Define the concept of
the digital divide, noting that it is not purely an issue of physical infrastructure. Discuss three distinct
socioeconomic or cultural factors that contribute to this divide even within geographic regions that
have functional internet access, and explain how a lack of access to computing tools harms an
, individual's economic mobility.
Correct Answer: The digital divide refers to the socioeconomic gap between populations that have
affordable, reliable access to modern information and communication technology (ICT) and those
who do not. Beyond physical infrastructure, factors contributing to the divide include: 1) Affordability
of hardware and subscription plans, 2) Digital literacy and education gaps that leave individuals
unable to navigate complex software, and 3) Language or accessibility barriers where digital content
is unavailable in native dialects or accessible formats for disabled individuals. A lack of computing
tools limits economic mobility by restricting access to online educational materials, preventing
individuals from developing modern job skills, and excluding them from the vast majority of
professional career postings and remote employment opportunities.
Question 4
A data science company uses machine learning algorithms to evaluate loan applications for a
commercial bank. The algorithm was trained on decades of historical lending data from the bank.
After deployment, auditors notice that the algorithm systematically denies loans to applicants from
specific historically marginalized zip codes, even when those applicants have high incomes and clean
credit histories. Explain how algorithmic bias occurs in this scenario despite the software engineers
not intentionally programming any discriminatory rules. Discuss how historical data can perpetuate
systemic biases.
Correct Answer: Algorithmic bias occurs when a computer program outputs systematically
prejudiced or unfair results due to biased assumptions made during the machine learning process or
flaws in the training data. Even though engineers did not write discriminatory code, the algorithm
was trained on historical lending data that reflected past human biases, discriminatory housing
policies (such as redlining), and socioeconomic disparities. The machine learning model identifies
statistical patterns within that historical data to predict loan default risks. Because historical
institutional biases linked specific zip codes to lower financial investment and higher default rates in
the past, the algorithm interprets the zip code as a negative predictive variable, thereby automating
and perpetuating systemic discrimination under the guise of an objective mathematical model.
Question 5
Public Key Cryptography (asymmetric encryption) is the mathematical backbone of secure
transactions on the modern internet, enabling protocols like HTTPS. Explain the operational
relationship between a public key and a private key. Detail the process of how a customer's web
browser securely sends a credit card number to an online retailer using this system, ensuring that
malicious actors intercepting the Wi-Fi traffic cannot read the sensitive data.
Correct Answer: Public key cryptography utilizes a mathematically linked pair of keys: a public key,
which can be shared openly with anyone, and a private key, which must be kept strictly confidential
by the owner. Data encrypted using a public key can only be decrypted by its corresponding private
key. When a customer inputs a credit card number into a browser, the online retailer sends its public
key to the browser. The browser uses this public key to encrypt the credit card data. Once encrypted,
the data becomes unreadable ciphertext. As the ciphertext travels across the internet or a public Wi-
Correct Answers Version 2026/2027
Question 1
An internet service provider (ISP) is upgrading a city’s network infrastructure. The engineers are
choosing between a hierarchical routing architecture and a fully mesh-connected network
architecture. Explain how the internet utilizes redundant routing to ensure fault tolerance. Describe
what happens to data packets when a primary router or physical fiber-optic cable is suddenly
severed during data transmission.
Correct Answer: The internet is designed as a distributed, redundant network where multiple paths
exist between any two points. This redundancy establishes fault tolerance, meaning the network can
continue to function properly even when individual components fail. Data is broken down into small
units called packets, each containing routing metadata (such as sender and receiver IP addresses).
Routers constantly evaluate network traffic and topology dynamically using routing protocols. If a
primary router or physical cable is severed, the surrounding routers automatically detect the loss of
connection and re-route the remaining packets along alternative paths. Packets may arrive out of
order or via different routes, but the receiving device reassembles them into the original file using
transmission protocols (TCP).
Question 2
A software development team is designing an online multiplayer game. They need to choose
between using the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) for
different components of the application. Contrast the operational mechanisms of TCP and UDP.
Explain which protocol is best suited for loading the player's account inventory data, and which
protocol is best suited for transmitting real-time player position coordinates during a match.
Correct Answer: TCP is a connection-oriented, reliable protocol that guarantees all packets arrive in
order and without errors by using a "three-way handshake" to establish a connection, tracking
packet sequence numbers, and requiring the receiver to acknowledge receipt. If a packet is lost, TCP
triggers a retransmission. UDP is a connectionless, lightweight protocol that sends packets
(datagrams) continuously without establishing a formal connection, tracking order, or checking for
delivery verification. For loading inventory data, TCP is mandatory because every single item asset
must load without error; missing data would corrupt the inventory state. For real-time player
position coordinates, UDP is ideal because speed and low latency are prioritized over absolute
reliability; if a position packet is dropped, it is immediately made obsolete by a newer position packet
a fraction of a second later.
Question 3
The digital divide remains a significant challenge for global technology equity. Define the concept of
the digital divide, noting that it is not purely an issue of physical infrastructure. Discuss three distinct
socioeconomic or cultural factors that contribute to this divide even within geographic regions that
have functional internet access, and explain how a lack of access to computing tools harms an
, individual's economic mobility.
Correct Answer: The digital divide refers to the socioeconomic gap between populations that have
affordable, reliable access to modern information and communication technology (ICT) and those
who do not. Beyond physical infrastructure, factors contributing to the divide include: 1) Affordability
of hardware and subscription plans, 2) Digital literacy and education gaps that leave individuals
unable to navigate complex software, and 3) Language or accessibility barriers where digital content
is unavailable in native dialects or accessible formats for disabled individuals. A lack of computing
tools limits economic mobility by restricting access to online educational materials, preventing
individuals from developing modern job skills, and excluding them from the vast majority of
professional career postings and remote employment opportunities.
Question 4
A data science company uses machine learning algorithms to evaluate loan applications for a
commercial bank. The algorithm was trained on decades of historical lending data from the bank.
After deployment, auditors notice that the algorithm systematically denies loans to applicants from
specific historically marginalized zip codes, even when those applicants have high incomes and clean
credit histories. Explain how algorithmic bias occurs in this scenario despite the software engineers
not intentionally programming any discriminatory rules. Discuss how historical data can perpetuate
systemic biases.
Correct Answer: Algorithmic bias occurs when a computer program outputs systematically
prejudiced or unfair results due to biased assumptions made during the machine learning process or
flaws in the training data. Even though engineers did not write discriminatory code, the algorithm
was trained on historical lending data that reflected past human biases, discriminatory housing
policies (such as redlining), and socioeconomic disparities. The machine learning model identifies
statistical patterns within that historical data to predict loan default risks. Because historical
institutional biases linked specific zip codes to lower financial investment and higher default rates in
the past, the algorithm interprets the zip code as a negative predictive variable, thereby automating
and perpetuating systemic discrimination under the guise of an objective mathematical model.
Question 5
Public Key Cryptography (asymmetric encryption) is the mathematical backbone of secure
transactions on the modern internet, enabling protocols like HTTPS. Explain the operational
relationship between a public key and a private key. Detail the process of how a customer's web
browser securely sends a credit card number to an online retailer using this system, ensuring that
malicious actors intercepting the Wi-Fi traffic cannot read the sensitive data.
Correct Answer: Public key cryptography utilizes a mathematically linked pair of keys: a public key,
which can be shared openly with anyone, and a private key, which must be kept strictly confidential
by the owner. Data encrypted using a public key can only be decrypted by its corresponding private
key. When a customer inputs a credit card number into a browser, the online retailer sends its public
key to the browser. The browser uses this public key to encrypt the credit card data. Once encrypted,
the data becomes unreadable ciphertext. As the ciphertext travels across the internet or a public Wi-
