The barrier is cultural differences.
John, growing up in America learned that eye contact is a way of respect and to show you are paying attention.
Where Cho, growing up in Asia, many Asian counties don't have this "custom" to call it that.
A lunar eclipse can last for a couple of hours and some minutes
The mechanism of enzymatic action within a single substance
The smallest item in the list would be organelles. Organelles are tiny structures within a cell, that help it to function. Example of organelles are-- nucleus, mitochondria, cell membrane to name a few. Cells are the basic unit of structure and function of all living things, therefore, cells would have to be placed second. They are microscopic. A group of similar cells that work together to perform a specific function, is known as a tissue. Therefore, tissue is next largest. Examples of tissues include, muscle tissue, epithelial tissue, adipose tissue. When different types of tissues work together to perform a function in the body, this group of tissues forms an organ. An example of an organ is the heart. Inside the heart are many types of tissue-- cardiac muscle,nerve, blood, connective, etc. The job it performs is to pump blood. When various organs work together to perform a specific function in the body, this makes up a system. An example is the circulatory system. In this system are many organs that work together. Arteries, veins, capillaries and heart are all part of the circulatory system. Its job is to circulate blood containing nutrients and oxygen to cells and to pick up cellular wastes. All the systems of the body comprise the organism. An organism is a living thing. It can be as tiny as a microbe, or a complex as a human. When referring to a multicellular organism, the correct order from smallest to largest is-- organelle, cell, tissue, organ, system, organism
Over utilized plants and animals are those plants and animals which are almost going out of existence or are already extincts as a result of over use by humans. Examples of over utilized animals include: West African Black Rhinoceros, Passenger pigeon, Sea mink, Tecopa pupfish, Pyrenean ibex and Tasmanian tiger.