Final answer:
Lines 103-124 are different from the rest of the poem because they describe a battle with sea monsters.
Step-by-step explanation:
The lines 103-124 in the poem are different from the rest because they describe a battle with sea monsters. The other options mentioned in the question, such as being written in a different language, being in a different poetic form, or expressing the seafarer's joy and contentment, are not accurate descriptions of the lines. The lines provide a distinct and exciting narrative of the battle with sea monsters, adding a thrilling element to the overall poem.