All of the following are evidence that a chemical reaction has occurred except
a. color change
b. formation of a precipitate
c. bubbles of gas
d. all of the above are evidence of a chemical reaction

The correct answer is A because color change is a physical change, when a substance changes color, the substance is still the same 

Ithink due to shortage of water

The virus is considered to be are living item since they have hereditary material dnas or rnas. they can imitate and change. they respond to boosts, for example, radiation, chemicals, and warmth. they have antigenic properties. they are proficient to duplicate with a same hereditary constituent.