The structures in humans that provide the ability to detect pain and therefore keep the body safe are called
chemosensors
nociceptors.
photoreceptors
thermoreceptors.

B. Nociceptors

Explanation:

Nociceptors are sensory neurons also known as "pain receptors" because they enable the body to detect the sensation of pain. These structures function by detecting the chemical signals released from a damaged tissue.

Nociceptors can be either external or internal. In humans, the external nociceptors are found in skin, mucosa, and corneas; whereas internal nociceptors are found in the joints, muscles, gut, bladder, and the digestive tract.

Moreover, there are different types of nociceptors according to their function. They can be chemical, thermal, mechanical, silent, and polymodal.

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