How do sepals protect a developing flower bud?

Sepals are the outermost floral organs that primarily serve to enclose and protect the unopened flower bud. Collectively known as the calyx, these structures form the outermost whorl of the flower.123

By surrounding the developing bud, sepals provide a physical barrier that shields the delicate internal reproductive organs—the stamens and carpels—before the flower blooms. While they are typically green and leaflike, which helps them blend into the plant's foliage, they are considered accessory, sterile appendages because they are not directly involved in sexual reproduction.1432

In some species, sepals may be separate (aposepalous) or fused (synsepalous) to form a protective tube around the bud. In certain plants, the calyx remains persistent even after the flower has bloomed and the fruit has begun to mature, continuing to provide support or protection.143