CHALLEGE - Find the eigth digit of the code.

123456789
Across
  1. 2. Dairy product that melts when heated.
  2. 4. It is delicious spread on toast.
  3. 6. Main ingredient in muesli and in porridge.
  4. 7. Product very rich in fats included in the Full English Breakfast.
  5. 8. Fraction of DER everyone should take in at breakfast.
Down
  1. 1. Wheat, corn, oats and others like those.
  2. 2. Called “Media Luna” in Argentina.
  3. 3. In “DER”, what does “E” stand for?
  4. 5. Full English Breakfast ingredient of plant origin.
  5. 9. Variable involved in the DER calculation.