Use complete sentences to explain what happens in the nervous system when your finger is hurt. Include an explanation of what a neuron is.

Nervous System: Tissue damage activates pain receptors in the skin. A signal is sent from the peripheral nerve, to the spinal cord where neurotransmitters or chemical messengers are released. This activates other nerves to pass a signal to the brain. The signals are relayed to the somatosensory cortex for pain, sensation, touch, etc.

Neuron: A neuron is a nerve cell that carries electrical impulses. Neurons are the basic units of our nervous system. Neurons have a cell body, dendrites, and an axon, which are nerve fibers. There are about 86 billion neurons in the human brain, which is about 10% of all brain cells.

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation: