What feature on fingertips helps primates manipulate objects more easily?

The feature on fingertips that aids primates in manipulating objects more easily is friction ridges. These ridges create a unique pattern on the skin surface known as fingerprints. Their primary function is to enhance grip and control. When a primate (including humans) grasps an object, the friction provided by these ridges allows for better traction, reducing the likelihood of slipping. This anatomical adaptation is particularly beneficial for activities that require precision, such as grasping small objects, climbing, or creating tools.

While flexion lines are creases that form in the skin due to bending, and dermal papillae are small, nipple-like projections that help anchor the epidermis to the dermis and increase the surface area for nutrient exchange, they do not directly contribute to the gripping ability of the fingertips. Frivolous ridges is not a recognized term in the context of skin anatomy. Thus, friction ridges stand out as the critical adaptation for enhancing dexterity and manipulation in primates.