How many sections of a job description are there

In a response of approximately 50 words, explain why it would be essential for the successful a/v technician to participate in additional coursework, presentations and seminars offered by equipment manufacturers as well as annual conferences attended by colleagues in the industry.

When is a chart legend used a. all the time b. whenever you are comparing data that is the same c. whenever you are comparing multiple sets of data d. only for hand-drawn charts

What are the three uses of a screw?