HORTICULTURE

Detailed explanation-1: -When two or more organs perform a common function by their physical and/or chemical interaction, they together form organ system. Many organ systems are then organised and form an organism. So, the correct order is: Cells-Tissues-Organs-Organ systems-Organism.

Detailed explanation-2: -The major levels of organization in the body, from the simplest to the most complex are: atoms, molecules, organelles, cells, tissues, organs, organ systems, and the human organism.

Detailed explanation-3: -Higher levels of organization are built from lower levels. Therefore, molecules combine to form cells, cells combine to form tissues, tissues combine to form organs, organs combine to form organ systems, and organ systems combine to form organisms.

Detailed explanation-4: -Life processes of the human body are maintained at several levels of structural organization. These include the chemical, cellular, tissue, organ, organ system, and the organism level.