Consider the human brain. Using the anatomical levels of organization-chemical, cellular, tissue, organ, organ system, and organism-name one "component" related to the brain for
that layer. For example, components of the brain at the chemical level would be the specific atoms or molecules that make up the brain.

A. Brain - Organ level

B. Neurons - Cellular level

C. Neurotransmitters - Chemical level

D. Neurons and neuroglial cells - Tissue level

E.Brain combined with the spinal cord and spinal nerves - Organ System level

Explanation: There are five levels of organisation of life; cell, tissue, organ, system and organism.

The smallest unit is cell. Neurons are nerve cells.

Aggregation of cells forms a tissue. Neurons and neuroglial cells aggregate to form nervous tissues and are hence at tissue level.

Aggregation of tissues forms an organ. Brain is an example of organ. It is formed from aggregation of nervous tissues.

Tissues aggregate to form organs while aggregation of organs constitute a system. The nervous system consist of brain combined with spinal cord and spinal nerves.

The nervous system release chemicals called neurotransmitters.