Volume is the amount of space inside a 3D shape. For a rectangular block, you can think of filling it with unit cubes: along the length you have L units, along the width W units, and along the height H units. The total number of unit cubes is L × W × H, so the volume is length × width × height. This multiplies all three dimensions to give the space inside. The other options mix up what you’re counting (area instead of volume) or introduce division or density, which don’t apply to this calculation.

The main idea behind a design brief is to clearly define what needs to be solved and set the direction for the whole design effort. It identifies the problem, states what the user needs, and lays out the project scope and constraints such as size, cost, materials, safety, and performance. With these elements in place, the design team has a concrete target and a reference framework to guide concept generation, evaluation, and development, ensuring the final solution fits real user needs within the given limits. Other activities like manufacturing steps and production planning belong to later stages of the process, once a concept is chosen. A marketing plan focuses on how the product will be launched and sold, not on defining the problem or guiding design. Legal compliance is important, but it’s part of the constraints rather than the core purpose of the brief.

Design for assembly means shaping a product so it’s quick and easy to put together in manufacturing. The core idea is to reduce the effort, time, and potential for error in assembling the product. This is best achieved by cutting the number of parts, so there’s less handling and fewer steps, and by using standard fasteners that are readily available and simple to install. Designing parts to locate and fit together easily, sometimes with self-assembly features or modular subassemblies, also helps speed up production and reduce costs. In short, the aim is to minimize assembly steps, lower part count, and rely on standard fasteners to make the assembly process faster, cheaper, and less error-prone. The other options don’t fit DFA philosophy because they either add complexity (more assembly steps, more unique fasteners) or ignore assembly considerations altogether, which would defeat the goal of making production efficient.

Risk assessment in health and safety is a systematic process: identify potential hazards, assess how likely harm is and how severe it could be, and decide on and put in place measures to control the risk so it is as low as reasonably practicable. A common way to reduce risk is to implement controls such as personal protective equipment, machine guards, and proper training so workers know how to perform tasks safely. This approach is proactive and helps prevent incidents before they happen. Choices that advocate ignoring risks, waiting until after an incident, or focusing only on financial risk don’t build the protective framework that risk assessment is meant to create.