Blank change colors in presence of an acid or a base

Acids turn the indicator red, pink, orange, and yellow, while bases turn it green, blue, and purple.

INDICATOR would be the answer your looking for.

c.the charges if the proton and electron and gravity

a) electrical > light, sound, and thermal< < < <

) the mechanical energy of the firefighter moving.< < < < a) electrical > light, sound, and thermal< < < <

c) both a and b.