Answer: Bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Explanation:
As it is given that both 
and HCl chemically combine together leading to the formation of NaCl, water and carbon dioxide gas. As the gas is forming and its formation will also form bubbles into the solution.
This formation of bubbles actually indicate that a chemical reaction has taken place. As molecules of a gas are held by Vander waal forces so, this gas will readily escape into the atmosphere.
Thus, we can conclude that bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Explanation:Photosynthesis is important because the earth and all of the creatures in the sea and land need the plants to be able to feed themselves with the help of the sun and with cellular respiration, those plants are able to take in the carbon dioxide that we give and make into oxygen with we need. there fore without them we would not be able to exist.
It is commonly known that our Galaxy rotates upon the sun because of gravity. The diagrams' arrows sort of describe it. Id suggest Gravity as the answer.
13. D
14. A
15. C
16. B
17. F
18. E
