Do different religions have separate heavens? Where do morals come from? What is the difference between Jesus in the Bible and in other scriptures?
These are just some of the questions the Religious Education Council of England and Wales (REC) says that secondary school pupils grapple with on a regular basis.
But the REC is warning that a shortage of religious education teachers could contribute to religious stereotyping and discrimination, leaving pupils at risk of becoming ignorant, or bigoted.
It says high quality specialist teaching about all faiths, beliefs and world views is essential in a diverse society and is launching a campaign to try to attract more teachers into the profession.
Government data shows that in 2017-18, only 405 of initial teacher training places in England for RE were filled - well below the target of 643; figures for Wales have not yet been published.
The figures come against a backdrop of schools struggling to retain existing teachers - last month a report found the number of qualified teachers leaving the profession (for reasons other than retirement) had increased from 6% (25,260) of the qualified workforce in 2011 to 8% (34,910) in 2016.
'The big mysteries of life'
For Lynsey Wilkinson, head of religious education at Redhill Academy in Arnold near Nottingham, RE is important, given the range of views and opinions to which pupils are exposed.
"We live in a dynamic ever-changing society full of different perspectives, beliefs and cultures," says Miss Wilkinson.
"Learning about these things helps the pupils in my classroom see the world clearly and helps them develop a genuine understanding about the world and the people in it.
"And that understanding will help them to shape the society of the future - a better society."
Miss Wilkinson says that while she does not have a religious faith herself, it's exhilarating to debate big questions of life with pupils.
"I don't consider myself religious, but there's an academic side to RE that's fascinating to me - the idea of approaching these huge concepts from an intellectual point of view is one I've developed a real passion for.
"I spend my day helping these tirelessly curious kids get to grips with the big mysteries of life, examining spiritual beliefs, walking them through abstract philosophical concepts and getting into spirited debates over morals and ethics."
'At risk of ignorance'
Rudolf Eliott Lockhart, chief executive of the REC, says specialist teachers are crucial for keeping young people properly informed.
"Without good quality religious education delivered by a qualified RE teacher, who provides accurate and balanced information about the array of different world views that make up modern Britain, young people are placed at risk.
"Not only are they at risk of ignorance that might lead to misunderstanding or even bigotry, but as they go through life, they risk basing their knowledge, understanding and opinions on sources that perpetuate inaccurate and misleading stereotypes. If and when those prejudices and falsehoods surface in the classroom, well trained teachers of RE are equipped to challenge and correct them.
"With information and opinion so freely available on social media and other online sources, pupils need to be taught to differentiate between sources that are reliable and reputable and those that are more likely to lead to religious discrimination and hatred.
"It is clear that in Britain today, we need to develop a better understanding of different faiths and beliefs so that we build more cohesive communities. In a world where religious literacy is now a vital skill in all walks of life, the shortage of qualified RE teachers is a deep concern and needs to be urgently addressed."
What does the government say?
A Department for Education spokesman said: "Religious education remains compulsory at each key stage for all state-funded schools, including academies and free schools, and we expect all schools to fulfil their statutory duties.
"In addition, we have changed the law and the requirements in schools so that they have to actively promote mutual respect and tolerance of those with different faiths and beliefs."
A spokesman for the Welsh government said: "We are currently reforming the way in which initial teacher education is delivered - putting in place new accreditation criteria and strengthening the ways in which schools and universities work together.
"An advisory board has also been established to consider issues of teacher recruitment and retention.
"We believe that this, together with a new curriculum, a new approach to our foundation phase and a commitment to professional learning will help us attract the very best teachers."