$1.$What is the difference between SEO and SEM?

$2.$ Using the search engine of your choice, and keywords of your choice, find an effective

search ad$.$ Also find one which you believe not to be effective. Describe why you feel

the former is effective, and the latter is not.

$3.$ Using an example of an organization or industry, what do you believe is the best search

engine to use for SEM?

$4.$ Using an example of an organization, explain how it might use the account, campaign

and group levels for its SEM activity. In other words, describe what would be at each

level using the organization as an example.