To prove that a certain fruit (in this case, an orange) indeed contains a certain compound (in this case, vitamin C); then the vitamin C should be extracted and isolated from the orange and must be confirmed by molecular analysis. The extraction process involves using chemicals (i.e. 6% MPA), and procedures such as centrifugation and filtration. Then the extract is stored and subjected to high-performance liquid analysis (HPLC) to measure the vitamin C content.
A food chain can usually sustain no more than six energy transfers before all the energy is used up. And so less energy is transferred at each level of the food chain so the biomass gets smaller.
