Tyrosinase is an enzyme that speeds up the transformation of the amino acid tyrosine into the black pigment melanin. It causes the black fur colour seen in some rabbits. When one set of rabbits was maintained at $30^{\circ}\text{C}$, $90\%$ of them had light fur colour. When a different set of rabbits was kept at $10^{\circ}\text{C}$, $90\%$ of them had black fur colour. Which hypothesis do these results support?
- AAn inhibitor is present in rabbit skin cells that can bind strongly to tyrosinase when the external temperature is $30^{\circ}\text{C}$.
- BAt $10^{\circ}\text{C}$ external temperature there are fewer tyrosinase-tyrosine complexes formed and less melanin is produced.
- CTyrosinase is an enzyme that is coded for by a gene that is switched off when the external temperature is $10^{\circ}\text{C}$.
- DTyrosinase is a temperature-sensitive molecule that is only activated when the external temperature is $30^{\circ}\text{C}$.