_____ is the basic structural and functional unit of all known living organisms.

Cell

The correct answer is Option (3) – Cell

The Cell is the basic structural and functional unit of all known living organisms.

Explanation:

• The cell is the smallest unit of life and is capable of carrying out all the processes necessary for an organism to survive and function.
• All living organisms, whether they are bacteria, fungi, plants, animals, or humans, are composed of cells.
• Tissues are groups of cells working together to perform a specific function, and bacteria and fungi are types of organisms that consist of one or more cells.

In summary, the cell is the fundamental building block of life, and it is the basic structural and functional unit of all known living organisms.