If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?
I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.