$(a)$ Distinguish between homologous and analogous organs.
$(b)$ State one evidence of organic evolution.

(N/A) Homologous organs are those organs which have a common ancestral origin and similar basic structural design,but perform different functions (e.g.,forelimbs of humans and wings of birds).
Analogous organs are those organs which perform similar functions and have a similar appearance,but have different ancestral origins and different basic structural designs (e.g.,wings of a butterfly and wings of a bird).
$(b)$ One evidence of organic evolution is the study of fossils (paleontology),which provides a chronological record of organisms that lived in the past and shows how species have changed over time.