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Mystery #1Tier 1-2kidneys / filtering / waste

What are your two kidneys quietly doing all day and night?

Right now, without you thinking about it once, all of your blood is being checked and tidied, drop by drop, over and over. Two organs about the size of your fists never take a break, not even while you sleep. What on earth are they so busy doing in there?

A colourful teaching model of a kidney cut in half, showing its inner filtering structure
Photo: Wagner Souza e Silva · CC BY-SA 4.0 · via Wikimedia Commons

Your guess

What do you think your kidneys are busy doing in there?

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