According to the principle of superposition, when two waves meet, they
a. reflect
b. refract
c. diffract
d. interfere

which are post-impressionist paintings? check all that apply?

explanation:

post-impressionism is a predominantly french art movement that developed roughly between 1886 and 1905, from the last impressionist exhibition to the birth of fauvism. post-impressionism emerged as a reaction against impressionists' concern for the naturalistic depiction of light and color.

hope this have a good day

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.