Answer and explanation:
1. sources of error- in the experiment, the amount of carbon dioxide released by east is monitored, a source of error could be the carbon dioxide present in the atmosphere which would interfere with the results.
2. baking recipes add sugars and molasses to provide carbohydrates for the yeast. this acts as a source of energy for the fermentation process.
3. the respiration of yeast could be monitored by measured the amount of sugar used or by measuring the amount of ethanol produced in the respiration process
4. high concentrations of sugar my inhibit yeast activity most likely because of the high osmotic concentration which prevents yeast from getting enough water for growth. as the osmotic concentration increases a yeast cell will reach a pont where water moves out of the cell.