لخّصلي

The chemical level is the simplest level of organization.An atom is the smallest unit of a chemical element (fundamental substance) that retains the characteristic properties of that element.At the cellular level we find that many diverse molecules may associate with one another to form omp1ex and highly specialized structures within cells called organelles.Each major group of biological functions is performed by a coordinated group of tissues and examples of organs, called an organ system.Tissues in turn, are arranged into functional structures called organs, such as the heart and stomach in animals or roots and leaves in punts.

The chemical level is the simplest level of organization. It includes the basic particles of all matter, atoms, and combinations of atoms called molecules. An atom is the smallest unit of a chemical element (fundamental substance) that retains the characteristic properties of that element. Atoms combine chemically to form molecules. For example, two atoms of hydrogen combine with one atom of oxygen to form a molecule of water.
At the cellular level we find that many diverse molecules may associate with one another to form omp1ex and highly specialized structures within cells called organelles. The organelles are suspended within the jelly-like cytoplasm of the cell. The cell itself is the basic structural and functional unit of life. In most multicellular organisms, cells associate to form tissue such as muscle tissue in animals. Tissues in turn, are arranged into functional structures called organs, such as the heart and stomach in animals or roots and leaves in punts. Each major group of biological functions is performed by a coordinated group of tissues and examples of organs, called an organ system. The circulatory and digestive systems are examples of organ system. Functioning together with great precision, the organ systems make up the complex multicellular organism.