Answer:
All of these choices are correct.
Explanation:
A cell can be defined as the fundamental or basic functional, structural and smallest unit of life for all living organisms. Some living organisms are unicellular while others are multicellular in nature.
A unicellular organism refers to a living organism that possess a single-cell while a multicellular organism has many (multiple) cells.
Generally, cells have the ability to independently replicate themselves. In a cell, the "workers" that perform various functions or tasks for the survival of the living organism are referred to as organelles. Some examples of cell organelles in all living organisms such as trees, birds, and bacteria include; nucleus, cytoplasm, cell membrane, golgi apparatus, mitochondria, lysosomes, ribosomes, chromosomes, endoplasmic reticulum, vesicles, cytoskeleton, etc.
Cytoskeleton refers to a structure consisting of filaments and tubules which help to maintain internal organization and support the shape of the cells. It comprises of three (3) main filaments and these includes: actin filaments, intermediate filaments and microtubules.
Generally, there are numerous evidence that cytoskeletal elements have ancient origins and they include all of the aforementioned facts.