HORTICULTURE

Detailed explanation-1: -Cell: The smallest organized unit of a living organism.

Detailed explanation-2: -All living things are made of cells, and the cell itself is the smallest fundamental unit of structure and function in living organisms.

Detailed explanation-3: -The body of a multicellular organism is organised at different levels, starting with the cell. Cells are organised into tissues, and tissues form organs. Organs are organised into organ systems and finally into an organism.

Detailed explanation-4: -Answer. The biological levels of organization in a complex, multicellular organism, from the smallest unit to the largest unit, are cells → tissues → organs → organ systems → organism.