Select the statements that explain why duplication is a driving force for evolution and the generation of new genes.
a. Genes duplicate and then diverge from the original sequence to create multigene families.
b. Duplication of a chromosomal region always results in novel gene functions.
c. Changes in gene function can occur when random fixed mutations are introduced into a new chromosomal environment.
d. Duplicated genes provide extra copies of DNA that are not constrained by an essential function.

Gene duplication delivers new genes and families of genes due to some arbitrary changes over some undefined time frame.gene duplication at various locations can create new genes with either advantageous or unsafe impacts. Arbitrary changes can prompt an additional duplicate of DNA bringing about dosage compensation where the deciding mutations can be lost.

Gene and genome duplications give a source of hereditary material for mutation, float, and selection to work on, making new evolutionary opportunities conceivable. Accordingly, many have contended that genome duplication is a prevailing element in the development of the evolution of complexity and diversity.

Thus, the correct answer is - a, c, and d.