Which is the full form of COPA​

So im doing this school challenge and the teachers said whats the average text a student gets a day so i need to get about 20 in a day but dont know how can you guys 2163371293

In which part of a professional email should you try to be brief, but highly descriptive?

On early television stations, what typically filled the screen from around 11pm until 6am? test dummies test patterns tests testing colors