Questions

In word, the mailing list is known as the Data source.

Sum of numbers in the outer circle in before Arc should come in inner circle patterns in the clock wise direction next Arc.

i.e, 9+6 = 15 comes in next arc of inner circle

7+3 = 10 comes in next arc of inner circle

In the same way, 4+2 = 6 comes in place of '?'.

The Indian Ocean consists of one gyre, the Indian Ocean (Majid) Gyre, which exists mostly in the Southern Hemisphere. It is named after Ahmad Bin Majid, the 15th-century Arab mariner. Following shows the Oceans and their respective Gyres

 Indian Ocean            -        Majid Gyre

North Atlantic Ocean   -       Columbus Gyre

South Atlantic Ocean  -       Prince Henry Gyre

North Pacific Ocean     -      Turtle Gyre

South Pacific Ocean    -       Heyerdahl Gyre