Explanation:

- Hercules was tasked to hold the sky, a task originally given to Atlas as a punishment.

- When Atlas returned from retrieving the golden apples, he saw Hercules trying to manage the heavy burden of the sky.

- The weight made Hercules visibly struggle, a task not easily managed, indicating strong effort.

- The word for Hercules's effort must reflect significant difficulty due to the sky's weight.

Let's consider the options:

- Tackling: Implies actively dealing with a problem, but not with a sense of ongoing difficulty.

- Coping: Suggests managing, usually with stress, but often implies some level of success.

- Struggling: Indicates ongoing difficulty under a heavy burden, which aligns with Hercules's effort.

- Seeking: Suggests searching, which doesn't fit the context of the effort to hold the sky.

?? Your chosen answer: 3 - struggling