In GCSE Science, students will look at energy and biomass in food chains. This is the last of three quizzes on that topic and it looks in particular at the carbon cycle.
It is quite possible that your body contains carbon atoms that were once breathed by a dinosaur. Or perhaps eaten by a king or queen or even excreted in dog poo. Yeuch! But how is this possible? The answer is one of the most important cycles for life - the carbon cycle. Our planet has only a limited stock of chemical elements and they are constantly being recycled in different ways. If they weren't, they would all have been used up long ago and the Earth would be an unchanging dead planet.