Answer:
The scientific term for a living thing is a(n) <u>organism</u>.
All living things are <u>made up of one or more cells</u>.
The simplest level at which life exists is <u>cell</u>.
Example of a multi-cellular organism is <u>human beings</u>.
Example of a unicellular organism is <u>bacteria like E. coli</u>.
<u>Cell membrane</u> surrounds a cell and separates it from its environment.
All cells perform various jobs or <u>functions</u>.
No, all cells are not alike but these cells share some basic similarities. For example: Neuron is very different from that of epithelial cell but they both have nucleus and other membrane bound organelles.
Differences between unicellular and multi-cellular organisms are as under:
1) Unicellular organisms are simpler than multi-cellular organisms. Multi-cellular organisms are complex.
2) In unicellular organisms a single cell performs all the functions required to sustain a life while in multi-cellular organisms a group of one type of cells perform only one function and other function is performed by another group of cells. These group of cells meant for a specialized function is known as tissue. Various tissues in combination form an organ. Various organs collectively form an organ system. These various grades of organization and specialized organs perform various functions and the co-ordinated work of all the organ systems sustain the life of a multi-cellular organism.
3) Unicellular organisms are less efficient than multi-cellular organisms.
4) Unicellular organisms may be prokaryotic or eukaryotic but multi-cellular organisms are always eukaryotic.
