As suggested by Maharishi Kanad and Democritus:

We got 'Atom" as the ultimate particle on the continuous division of any matter.

But was rejected by the Aristotle and due to the great influence of Aristotle that time, public also discarded this theory.

But after 2000 years later – 'Atom' was considered to be the indivisible entity of matter up till the Dalton's theory.

Integrative Level (Levels of Organization)

Integrative level or Levels of organization

It is a set of phenomena emerging from pre-existing phenomena of a lower level.
The levels concept is an intellectual framework for structuring reality.
It arranges all entities, structures, and processes in the universe, or in a certain field of study – into a hierarchy, typically based on how complex their organization is.

Each entity is three things at the same time:

Made up of parts from the previous level,
It is a whole in its own right,
And it is part of the whole that is one the next level.

Biological Levels of Organization

These are said to be the biological levels of organization which extends from Atom to Biosphere.

Where we have several departments based on their fields of study.

For instance, we have Chemistry and Biochemistry, where mainly we deal with atoms, molecules and macromolecules.

These are the center of science; therefore, chemistry is said to be the central science (center of science).

Biological organization is the hierarchy of complex biological structures and systems that define life.

These are the traditional hierarchy that extends from atom to biospheres.

Each level in the hierarchy represents an increase in organizational complexity, with each "object" being primarily composed of the previous levels' basic unit.

Without this necessary degree of organization, it would be much more difficult – and likely impossible – to apply the study of the effects of various physical and chemical phenomena to diseases and physiology.

A change at the cellular level can affect an entire organism.

These applications extend into the ecological levels as well.

Theoretically, a change in one atom could change the entire biosphere.

Atom was considered to be the indivisible entity of matter up till the Dalton's theory.

As because in 1897, JJ Thomson discovered electrons (subatomic particle) and stated that atoms are divisible.

For levels smaller than atoms – we have subatomic particle.

Then new subatomic particles proton, electron and neutron were discovered so now atom is divisible.

For levels larger than biosphere or ecosphere, we will have to go on cosmic physics (study of universe), where we will study planets, stars, galaxies and so on.