Choose two key fundamental concepts about physical and chemical properties.

a. Physical properties are permanent changes that cannot be undone without using intense scientific processes.
b. Chemical properties cannot be easily observed, and often require some sort of specialized test to determines them.
c. Physical properties are basic observations that can be made using the five senses.
d. Chemical properties can be easily undone.

c. Physical properties are basic observations that can be made using the five senses.

d. Chemical properties can be easily undone.