Describe the structure.

Hint: Life processes of organisms i.e both animals and plants are maintained at various levels from lower to higher levels of structural organisation. This organization involves chemical cellular, tissues, organs and organ systems at different organism levels. Lower levels of the organization are involved in the building of the higher levels of an organization.

Complete answer:
The structure given above describes the levels of structural organization of a plant. All organisms i.e both plant and animals have various levels of structural organization that are formed on each other which means that cells are made by the combination of molecules, tissues are made up by grouping of cells, tissues combine to build organs and organs combine to develop the organ system and finally, organisms are developed by the combination of the organ system.
Different levels of structural organization:
Cells: A cell is defined as the smallest and independent structural and functional unit of a living organism.
Tissues: When several similar types of cells group together to perform certain functions then a structure is formed which is referred to as tissues.
Organs: When a similar type of tissue is collected in a cluster to perform a special function then it is termed as an organ.
Organ system: A collection of organs that perform together to accomplish major functions of the body or to meet the body's physiological needs.

In the above structure, cells (the fundamental unit of life) combine to build tissue. A similar type of tissues then groups together to form an organ i.e the leaf of the plant. These organs i.e the leaves combine to form a branch of the plant (organ system) and finally, many branches combine to make a complete plant (organism).

Note: The students might get confused between the relationship between the function and the structure of the cells present in the tissue. Structurally, In epithelial tissue, cells are packed tightly with each other. Several functions are performed by the cells present in the epithelial tissue which include absorption, secretion, protection, sensory reception and excretion.