Final answer:
Merkel cells, or Merkel's disks, are crucial for detecting fine touch and are abundant on the fingertips and lips, playing an essential role in facilitating proper gripping of objects.
Step-by-step explanation:
Merkel cells are mechanoreceptors that facilitate proper gripping of objects. Merkel cells, also known as Merkel's disks, are found in the more upper parts of the skin, particularly abundant on the fingertips and lips, where they detect fine touch. This sensory detail is crucial for gripping objects correctly, as it helps in adjusting the pressure and maintaining a secure grip without dropping or crushing the items.
On the other hand, Ruffini endings detect stretch and deformation within joints, Meissner's corpuscles are responsible for touch and low-frequency vibration, and Pacinian corpuscles react to transient pressure and high-frequency vibration. It's important to note that all these mechanoreceptors except Merkel's disks are encapsulated. Therefore, when considering the statements provided, the true statement that corresponds to the role of Merkel cells is "b. Merkel's disks are abundant on the fingertips and lips."