Explanation:
A physical change is a change that alters the physical properties of matter most especially the state and the form. This change has the following attributes.
- it is easily reversible
- leads to the production of no new kinds of matter
- involves no change in mass
- requires little energy
Therefore, some of the examples of physical changes are:
- boiling
- melting
- freezing
- condensation
- sublimation
- magnetization of metals
- breaking of glass
- cutting of wood
the answer is B. Atmosphere
An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12. The mass of any isotope of any element is expressed in relation to the carbon-12 standard. For example, one atom of helium-4 has a mass of 4.0026 amu. An atom of sulfur-32 has a mass of 31.972 amu.
