How does a dog recognise the opposite sex if they can't smell their butt? Is it healthy to eat your own boogers? Plus, is it possible to inter-breed species?

Do your eyes water when you're getting a wax?

In this episode Dr Karl makes a brand new, ground breaking, mind blowing discovery that has changed his life. 

How scientists know what the temperature was in the years before records began? What role does cattle have on the impact of climate change? And how have the current bushfires affected carbon levels?

Why do we feel like vomiting after rigorous exercise? Does distance or speed burn more calories? Plus, the movement of air pollution.

Does smoke benefit the soil? Plus, what can we expect to see in the future for fire prevention?

Linda Marigliano and Dr Karl take your questions for one last time together.

Coconut oil, inhaling smoke and why you might feel tired when you're doing nothing?

Chernobyl Exclusion Zone, what is dark matter and what would happen if flies don't exist?

How much information can your brain hold? How do genetics work and does the clitoris have multiple purposes?