A weakened version of a pathogen that is used to build antibodies for future defense is known as which of the following? *

Cell is the basic unit of life while organs are the group of tissues formed from cells.

One example is the neuron, a cell that composes the nervous system. For example a brain, an organ composed of thousands of neural fibers and glial cells that performs many important organismic functions.
Neurons are specialised cells that have dendrites, axons and terminal buttons that sends and receives stimuli from the environment and transduces it into a meaningful information and understand the complexities which the brain now functions.