What technique do artists use to create rhythm

When the percussion section played the theme, the theme was less recognizable since most percussion instruments aren't tuned to a pitch the instrument sounds included drums and cymbals both a and b neither a nor b

What is the term for a recurrent musical section between various contrasting sections? a. concerto grosso b. basso ostinato c. fugue d. ritornello

When you shoot using the lowest number possible for your aperture what is it called