Hydrogencarbonate indicator is sensitive to changes in carbon dioxide concentration. It is red at normal atmospheric levels of carbon dioxide, but turns yellow when carbon dioxide levels increase.
A physiologist set up an experiment to investigate the respiration rates of different tissue samples isolated from a mammalian subject. The tissues were incubated in physiological saline at 37∘C37^{\circ}\text{C}37∘C. The results after 30 minutes are shown in the table below:
| Tissue Sample | Colour of hydrogencarbonate indicator |
|---|---|
| Active cardiac muscle | Yellow |
| Tendon | Red |
Explain why the result for the active cardiac muscle tissue is different from the result for the tendon tissue.