Firsts

123456
Across
  1. 3. First number
  2. 4. First letter of the alphabet
  3. 5. Start of a new day
  4. 6. First meal of the day
Down
  1. 1. Absence of sound
  2. 2. First word of a baby
  3. 3. Vast watery expanse
  4. 6. BANG First light in the universe