Naturalisation is decided partly by an exam, and the exam is narrower than it looks: a fixed, published list of questions, a known pass mark, and an interview that is as much a test of spoken English as of the answers themselves. Pick the country you are applying in — each track works through the official question bank and rehearses the interview out loud.
In both countries, passing the knowledge test is not the whole of it. In the US the interview also assesses your spoken, read and written English, and each part is scored separately. In the UK the Life in the UK Test does not satisfy the English language requirement: you also need B1 or above, through an approved qualification or a degree taught or researched in English. Sort out the English side early — it is easy to underestimate.
Questions whose answer depends on who currently holds office — the president, your senators, the monarch, the Prime Minister — are not in the quizzes, because a fixed answer key would go out of date. Look those answers up yourself from an official source, close to your test date.
Zestly is an independent study tool. It is not affiliated with USCIS or any US government agency, nor with the Home Office, UK Visas and Immigration or any official test provider, and it is not a test centre. Nothing here is legal or immigration advice: eligibility, exemptions, fees, booking and the conduct of your test or interview are matters for the official authorities, and for an immigration attorney, accredited representative or adviser if you need one.