what does it mean when it's said that "this voucher admits up to 4 visitors"? does it mean that no more than 4 people could visit?

Ais a survey that focuses on only a small portion of the population, and the results are generalized for the larger population.

When reading a textbook blank. a) it’s safe to assume that the ingot is not biased b) you should watch for fallacies in information and author bias c) you should fact check everything you read d) it is understood that academic sources are not biased

In russia which of these challenges affects the transportation of both petroleum products and other goods?