In a personal computer, which components provide expansion capability by allowing additional circuit boards to be inserted into the system unit?

Introduction / Context:
This question focuses on the physical structure of a computer system unit and how hardware can be expanded. Many personal computers allow users to add extra capabilities, such as better graphics, sound, network interfaces or storage controllers. These additions are often made by plugging expansion cards into special connectors on the motherboard. Understanding the correct term for these connectors is an important part of basic computer hardware knowledge.

Given Data / Assumptions:

• We are dealing with a standard desktop or microcomputer system.
• The question asks which components provide expansion capability.
• Options include sockets, slots, bytes, none of these and heat sinks.
• We assume a basic understanding of motherboard layout and expansion cards.

Concept / Approach:
On a motherboard, long narrow connectors called expansion slots are used to hold expansion cards. Examples include PCI slots and PCI Express slots. These slots provide electrical connections and physical support so that new hardware can be added. Sockets are used for chips such as the central processing unit, not for expansion cards in general. Bytes are units of data, not hardware. Heat sinks are used to dissipate heat from chips and have nothing to do with expansion capability. Therefore, the correct term for components that provide expansion capability is slots.

Step-by-Step Solution:
Step 1: Visualise the inside of a desktop computer. On the main circuit board, or motherboard, you see several long connector strips where circuit boards can be inserted. Step 2: These connectors are called expansion slots. Common examples include PCI and PCI Express slots for graphics cards and other expansion cards. Step 3: When you add a new graphics card, sound card or network card, you plug the card into one of these expansion slots, thereby expanding the computer capabilities. Step 4: Sockets on the motherboard, by contrast, are usually designed to hold integrated circuits such as the CPU or memory modules, and are not generally described as providing overall expansion capability. Step 5: Bytes are units of digital data and have no physical form, so they cannot be physical components for expansion. Step 6: Heat sinks are metal components attached to chips to remove heat and keep them cool. They do not provide connectivity for new devices. Step 7: Option b, slots, therefore best matches the idea of expansion capability through additional cards.

Verification / Alternative check:
Most hardware manuals and introductory guides to computer assembly explicitly state that expansion cards are installed in available expansion slots on the motherboard. The word slot is repeatedly used to describe these connectors. In contrast, the term socket is reserved for components like the CPU socket or memory sockets, which usually support required components but are not described in textbooks as the main expansion feature of personal computers. This confirms that slots is the term the question is targeting.

Why Other Options Are Wrong:
Sockets do hold important chips but are not the primary mechanism for adding optional new features through expansion cards. Bytes refer to a quantity of data and have no physical presence. The option none of these is incorrect because one of the listed terms is clearly correct. Heat sinks are part of the cooling system and do not add new functions to the computer.

Common Pitfalls:
Students may confuse sockets and slots because both are connectors on the motherboard. A useful way to remember the difference is that slots are usually long and narrow for cards, while sockets are often square or rectangular for chips. Another pitfall is to overthink the question and consider abstract terms such as bytes, forgetting that the question clearly refers to physical components that provide expansion capability.

Final Answer:
In a personal computer, expansion capability is provided by slots on the motherboard where additional cards can be inserted.