Final answer:
An Acid perm is better for fragile hair, as it is gentler and ensures a slower processing time, creating soft, natural curls without excessive damage. Other perms such as Alkaline, Exothermic, or Root perms are less suitable for delicate hair or may not meet the needs for soft curls.
Step-by-step explanation:
For fragile hair that is suited for soft, natural curls with a slower processing time, an Acid perm is the better option. These perms have a pH level closer to that of natural hair, making them gentler during the chemical process. Acid perms are formulated for delicate hair types and are less likely to cause damage compared to other types of perms. They work at a lower pH, which slows down the processing time but also reduces the chance of hair breakage and damage.
An Alkaline Perm may cause more stress on fragile hair due to its higher pH level. The Exothermic Perm generates heat, which speeds up the chemical reaction, potentially leading to stronger curls but it can be more damaging for delicate hair. A Root Perm is intended to add volume to the roots, not necessarily to create soft, natural curls or to be gentle on fragile hair.