Which of the following correctly describes the importance of demonstrations to scientific investigation?

a- a demonstration shows how something works, often including models

b- in a demonstration, the effect of one thing on another is measured

c- in a demonstration, empirical data is collected

d- a demonstration is a process involving scientific investigation

A- A demonstration shows how something works, often including models

Explanation:

A demonstration allows, through experimentation, to show how nature works and in that way can include the explanation of scientific theories that explain the set of observed facts, that is, it serves as a demonstration of the underlying scientific principles.

a.   mass number from atomic number