The line that seperates one air mass from another is called a boundary.
The mass of tissue that separates the pleural cavities is called the mediastinum. It contains the heart, great vessels, esophagus, trachea, and other structures within the thoracic cavity.
This would be called a mass extinction or mass die off.This would be called a mass extinction.
Assembly Line (OW)
The Ford method of mass production on a moving line was called the assembly line. It revolutionized manufacturing through the use of interchangeable parts and a sequential process that increased efficiency and reduced production time.
The zone that separates two air masses when the denser and cooler mass is replacing the warmer mass as it advances describes the cold front. It is a boundary line that is between cold air and a warm air mass where the cold air pushes from under and behind as it advances.
I think he invented the assembly line...
I assume you're referring to the bold line that runs down the right side of the periodic table. If so, there isn't really a name for them. The line separates elements on the left side (which are metals) from elements on the right side (non-metals). The elements directly on the Hays-McDaniel Line are sometimes referred to as "metalloids".
a front.
A balanced scale, which compares the mass of one object with that of another.
The leading edge where one weather system meets another is called a front. It marks the boundary between two air masses with different temperatures and humidity levels. When a front passes through an area, weather conditions can change rapidly.
Usually, large numbers of identical products are made on a production line or assembly line.
It is not one machine, but a series of machines, called an assembly line.