Question

what characteristic of stars determines its life cycle? brightness color gravity size

Explanation:

The life cycle of a star is primarily determined by its mass (related to size). Larger stars have more fuel but burn it faster, leading to shorter, more violent life cycles, while smaller stars (like our Sun) have longer, more stable life cycles. Brightness is related to both size and distance, color is related to temperature (which is related to size/mass), and gravity is a result of mass but the key determinant of the life cycle is the star's size (mass).

Answer:

size