Where does the head (melody) begin? Is there improvisation? If so, how many different instruments improvise?

jazz style it best represents and why (bebop, swing, hardbop, cool jazz, etc.) Provide analysis on the music itself: what instruments are being used, is major/minor, describe texture, is it fast/slow, loud/soft, etc. Talk about the form. Where does the head (melody) begin? Is there improvisation? If so, how many different instruments improvise? Does the head return? Any other major features of the music. here the video https://www.youtube.com/watch?v＝0Q7J4PgrRsY&list＝PL-4U2d6ASRHn-h6UdaKkKnaAhg2T2kxAj&t＝2s