Explanation

#define PI 3.14

This is the correct syntax for defining a constant using the C preprocessor directive.

It replaces every instance of PI with 3.14 before compilation begins.

Explanation

Justify alignment evenly spaces text between the left and right margins, making both edges straight.

It gives the document a clean and professional appearance, commonly used in newspapers and reports.

Explanation

BCNF is a stronger version of the 3rd Normal Form; it handles certain anomalies that 3NF does not.

It ensures that every determinant is a candidate key, improving data integrity.

Explanation

The Shift key is used with letter keys to type uppercase letters.

It also allows access to the upper symbols on keys (like @, #, etc.).

Explanation

In Consolidated Data Distribution, all data is stored at one central site.

This simplifies management but may reduce access speed for remote users.

Explanation

Let's calculate:

F7 = 12

H12 = 30

Formula: F7 * H12 = 12 * 30 = 360

Explanation

An index helps the database quickly locate rows in a table without scanning the entire data.

It improves query performance by providing direct pointers to the data rows.

Explanation

UNIX is a multitasking operating system that supports multiple users and command-line interface (command drivers).

It is widely used in servers and academic environments due to its robustness and flexibility.

Explanation

Supercomputers are the most powerful computers, capable of performing trillions of calculations per second.

They are used in research laboratories for complex tasks like climate modeling, simulations, and scientific research.

Explanation

Scratch is a visual programming language where users create programs by dragging and connecting code blocks.

It is mainly used for educational purposes to teach programming concepts in a simple, interactive way.