Caterpillars feed on nettle leaves. In an investigation, 15 caterpillars were kept in a container with 850 grams of nettle leaves for two weeks. A student measured the total mass of the nettle leaves and the total mass of the caterpillars at the start and at the end of the two weeks. The results are shown in the table below.
| Mass in grams at start | Mass in grams at end | |
|---|---|---|
| Nettle leaves | 850 | 350 |
| Caterpillars | 50 | 110 |
Explain why the decrease in the mass of the nettle leaves is much greater than the increase in the mass of the caterpillars.
