A solid is placed in a solution. Which observation most likely indicates that a chemical reaction has occurred?
.
The size of the solid has rapidly decreased
The color of the solution has not changed.
The solid has bubbles forming on its surface.
The temperature of the solution stays the same.

the solid has bubbles forming on the surface

Explanation:

all of the other options are physical changes

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

it is a negative acceleration