Answer to Question 1
monophony (monophonic)single, unaccompanied melodyfor example, one singer or instrumentalist performing a melody as a solo without accompaniment, or a group of singers and/or instrumentalists all performing the same melody in unison without any accompaniment.
heterophony (heterophonic)two or more voices or instruments elaborating the same melody in different ways at the same timee.g., the heterophony between the deacon and the congregation heard on Amazing Grace.
polyphony (polyphonic)two or more different melodies at the same timefor example, in New Orleans-style jazz of the early 20th century, Javanese gamelan music, and European classical/art music of the renaissance period between 1450 and 1600 and the late Baroque (J.S. Bach being a master in this style), e.g. Illuman tiyu.
Homophony (homophonic)one dominating melody with accompanimentfor example, typical folk and popular musics throughout the world, e.g. Muyu muyari warmigu after :46, the solo female voice at this point begins to be accompanied by an ensemble playing chords and rhythm background.
Answer to Question 2
Chords plus the melody create harmony.
A Crab-eating Macaque, an old world species of monkey native to Southeast Asia
Clinal maps of ABO allele distributions in the indigenous populations of the world.
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Matthew Ritchie, No Sign of the World.
Paleogene world
The Vast World Ocean