Is bread rising a chemical change or physical change

Chemical. Things within the bread are having chemical reactions, such as the yeast reacting to the heat and baking.

There is definitely a chemical change taking place during baking, and that is the conversion of baking soda (sodium bicarbonate, NaHCO3) to carbon dioxide (CO2).

Explanation:

Hope this helps :)

a. a primary source combines several different accounts of an event. b. a primary source generally benefits from having been written after an event.

explanation:

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)