Question

Name the following:
 a)Largest known cell
 b)A unicellular organism

Answer 1

Hint:(i) Cell: It is the basic functional and structural unit of life. All the body functions depend on the cell. Cells to the formation of tissue$ \to $organ$ \to $organ-system$ \to $organism.
(ii) The organisms in which a single cell performs all the body functions are called unicellular organisms and the organisms in which group of cells or multiple cells perform body functions are called multicellular organisms.

Complete answer:
The largest known cell is the egg of the ostrich. Ostrich eggs are 6 inches (15cm) in diameter and can weigh up to 3 lbs (1.3kg). Eggs are laid in a communal nest called a dump nest which can hold up to 60 eggs at one time.
The largest egg in the human body is ovum. It is a female reproductive cell and is non-motile i.e. it is not capable of showing any kind of movement. When egg and sperm fuse during fertilization, a diploid cell called zygote is formed, which rapidly grows into a new organism.
Unicellular organisms unlike multicellular organisms consist of a single cell. They fall into 2 general categories: Prokaryotic organisms and Eukaryotic organisms. All Prokaryotes are unicellular and are classified into bacteria. Many Eukaryotes are multicellular but some are unicellular such as protozoa, unicellular Algae, unicellular fungi. Unicellular organisms are thought to be the oldest forms of life.
Most unicellular organisms are of microscopic size and are thus classified as microorganisms.

Note:Ostrich egg shell has a long history of use by humans as a container and for decorative art work. These eggs are not commonly ate. In unicellular organisms a single cell is capable of performing all the body functions.