Questions

A candidate key is a column, or set of columns, in a table that can uniquely identify any database record without referring to any other data. Each table may have one or more candidate keys, but one candidate key is unique, and it is called the primary key.

Variable costs are expenses that vary in proportion to the amount of goods or services that a business produces. 

Examples of variable cost include labor, packaging and raw materials.

Describe your ideal job?

You should use this question to relate to the post you applied and give them the feel that this is close to your ideal job. So align your wonderful ideal job reasons to the responsibilities of the job posting. 

This is a question that you can use to add some humor or do a icebreaker like just joking that your ideal job is to work in a space station or would like to work in Hollywood but after a quick laugh give a realistic answer like my ideal job is where i get more responsibilities, enhance my skills and grow, and of-course you can add saying you would like to be part of a team where work is fun. If you want to go further, You might add at the end you heard good things about the work environment in the interviewing company.

Burning gasoline is the only process that involving in a chemical change in the given options. A chemical change is a change in the starting substances that are called reactants from the formed new substances that are called products. 

The highway transportation system has helped to reduce traffic deaths with its easy flow of traffic under rash driving rules and also it helped to country economically.