Question

which sentence accurately describes star clusters? stars appear brighter. stars form large groupings. stars form at different times. stars form from different nebula.

Explanation:

Star clusters are defined as large - groupings of stars. The brightness of stars in a cluster can vary, stars in a cluster can form at different times but this isn't the defining characteristic, and while stars can form from different nebulae, the key aspect of a star cluster is the large number of stars grouped together.

Answer:

Stars form large groupings.