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toward the stomach because they are thin and flexible. Stomach muscle
cells help churn food, while other stomach cells produce juices to break

down food. All these cells work together, each shaped and structured for
their specific function, making the body's systems work properly. This
shows that a cell's shape and size are closely related to the job it performs in
the body.

You have learned that cells differ in structure and function. But how do
Science these cells together make a complete living body?
Bytes

Testimony WHAT ARE THE LEVELS OF ORGANISATION IN THE BODY OF A LIVING
In 1665, Robert Hook first ORGANISM?
used the term “cell”
when observing a thin The body of a living organism is organized in a simple and clear way. A cell is
slice of cork under his the basic unit of life, just like a brick is the basic unit of a wall. When many
microscope. Much later,
scien sts discovered that similar cells come together, they form a tissue. Different tissues then
not all living things are combine to form an organ, such as the heart or stomach. Several organs
made of many cells.
Some, like amoeba and work together to form an organ system that performs a big job for the body,
bacteria, consist of just like digestion or breathing. All the organ systems together make a complete
one cell and are called living organism, which can be a plant or an animal. This organization helps
unicellular, while plants
and animals that have the body function smoothly and efficiently.
many cells are called So, the levels of organisations are:
mul cellular. This
discovery helped Cell Tissue Organ Organ system Organism
scien sts understand how
complex life begins with These levels of organisation help us understand how simple building blocks
simple structures. like cells come together to form a complex living being.

WHAT ARE MICROORGANISMS?

Some living things are made up of just one or a few cells, and they are so
small we cannot see them without a microscope. These tiny living things are
called microorganisms. Some microorganisms, like bacteria and amoeba,
have only one cell and are called unicellular. Others, like certain fungi and

algae, have many cells and are called multicellular. Microorganisms are
found everywhere—in water, soil, air, and even inside our bodies! Their cells
can be similar to plant and animal cells, but many have unique features to
help them survive in different environments. Scientists use powerful

microscopes and special tools like foldable paper microscopes called
foldscopes to see these tiny cells and learn about the microscopic world
around us. Let us now take a closer look at the fascinating world of
microbes.

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