comprised by or comprised of? which is correct? if both are, what's the difference?

what is the difference between unity and solidarity? which one fits more as a motto?

What's the difference between collaboration and coopertation? can i use technical collaboration between two companies or coopertaion fits more?

[BEC] discrimitated or not? I‘ve been preparing for bec higher this year, and i wonder if i post my homework here, maybe someone would be willing to correct my errors~that'll be nice! This homework is about a job applicant who has strong foreign accent be tourned down as a telephone operater. He thought he was being discrimated. Here's my homework: In this specific case, I don't think this man was discrimitated. If I were in the employer's shoe, I might consider that people who call in may have difficulties understanding his heavy accent. Besides, it may leave a bad impression to the clients or potienal clients that the firm is being unprofessional. I think if the job applicant is really equipped with good English skills, he should probably search for a job which requires better writing skills other than oral ones. Any suggestion would be *loved*

First notebook entry: Introducing myself been working for 5 years after university graduation. Want to improve my bussiness English a little bit, cause I constantly communicate with foreign customers/providers.