蛋：大自然的完美发明

The egg is perhaps nature’s most perfect life support system. These remarkable structures nurture new life; protecting it from the outside world at the same time as allowing it to breathe. They are strong enough to withstand the full weight of an incubating parent and weak enough for a hatchling to break free. But how is an egg made? Why are they the shape they are? And perhaps most importantly, why lay an egg at all? Piece by piece from creation to hatching, host David Attenborough reveals the wonder behind these incredible miracles of nature.