Which of the following always indicates that a physical change has taken place ? a) rusting b) burning c) melting d) changing color

The correct answer option is C) Melting.

Explanation:

Physical changes can be defined as the changes which affect the form of a chemical substance but not its chemical composition. These are the changes in which no bonds are broken or formed.

Melting is a physical change. Taking an example of melting ice: water simply changes its physical state but its chemical composition is same for both Ice and liquid water.

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is

3. dark matter

empty space could also be a simple vacuum