D) nerve tissue neurons brain central nervous system human being
2)
Which is the SIMPLEST level of organization in a human being?
A)
cells
B)
organs
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tissures
ht
D)
organ systems
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5

A

Explanation:

The human body has many levels of structural organization: atoms, cells, tissues, organs, and organ system. The simplest level is the chemical level, which includes tiny building blocks such as atoms. Cells are the smallest functional units of life.

The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.

d organ system

Explanation:

put a thanks and branilest

answer///unconditioned stimulus;