Andre adds a spoonful of baking soda to a glass of vinegar. bubbles begin to appear in the vinegar. the bubbles signal the formation of a(n)

Expanation - The vinegar, an acid, chemically reacts with the baking soda, a base, resulting in the formation of carbon dioxide gas (which causes the bubbles) and water. So, the bubbles signal the formation of a compound, carbon dioxide.

pie chart because it is in percents ( % )

the answer is d.) potassium