Please choose the correct ending to complete the given sentence: Health: [header] How to get freckles [title] Understand the cause. [step] Freckles are a hereditary trait caused by an uneven distribution of skin pigmentation. A freckle occurs when there is a large concentration of the melanin pigment underneath one spot on your skin.

Ending1: Melanin pigmentation can be caused by one of two factors: a combination of genetics and physical activity. Genetics and physical activity both affect freckles. Ending2: [substeps] Most natural freckles are small and essentially harmless. They tend to show up on areas exposed to sunlight, like your face, and these are probably the type you're longing for. Ending3: Freckles can cause the skin to lighten, or change colors from a normal shade to a darker shade. [substeps] Freckles often have no identifiable cause. Ending4: Freckles will often become noticeably darker if your skin reflects too much melanin. Being curious about freckles can help you have a good look at your freckles and diagnose the underlying causes.

Answer format: ending1/ending2/ending3/ending4