What can be observed only by observing its effects on gravity? dark matter a solar nebula gas and dust a planetesimal

The correct answer is dark matter.

Explanation:

Most of the universe comprises dark matter, that is, approximately 85 percent. The dark matter cannot be witnessed and the scientists are sure regarding the formation of dark matter. However, its influence on gravity can be witnessed. In the absence of dark matter, it would not be possible to hold the galaxy in combination. Therefore, it can be said that dark matter can only be witnessed by noting its influence on gravity.

dark matter

Explanation:

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e