define segregation of duty and how it affects a company

If you have BPP questions you presumably also have answers? ( I don't and I am not familiar with a question shesha.) If you're asking what is meant by "segregation of duties" see the notes - page 63 (the pdfs are searchable so you can find references). Understanding that it is a control activity would go some way to saying something about how it affects a company. However, it seems unlikely that you would see such a general question ("a company" would be any company rather than one given in a scenario).