7. Challenge yourself: You have already learned that mutation is one source of variation in a population. Based on what you have just seen,
what is a second source of variation?

the cover letter for a job search includes the skills one has for the particular job. including a cover letter is always a good idea, as it describes the ability to perform a task, and the employer can easily fetch the intention of the job you want to do.  

the cover letter is very important to be included in the job search document. hence, i strongly with the statement.