One agent of chemical weathering is which combines with water to form carbonic acid

Chemistry worksheet - i am not sure what they are asking for exactly?

Asuspension of yeast cells is being grown under anaerobic conditions such that glucose is degraded to ethanol and carbon dioxide. if one wishes to follow this process by monitoring the release of 14co2, at which positions in the glucose molecule would the 14c label need to be incorporated?

Condensation happens when water vapor cools. true or false? ?