The children are posing gives less details than the first sentence.
This justifies what answer for what question? Q & A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Premise: "Two adults and two children pose on a pile of rocks."
Hypothesis: "The children are posing."
Do we know that the hypothesis entailed by the premise?
yes