Methane is the primary component of natural gas and is used to produce heat and electricity around the world.
An intensive property would be something like color. You could have 1 mol or 20 mols of something and the color would be the same. Think intense color like silver or gold. Another example is density. 1 mol of iron has the same density as 28 mol of iron.
An extensive property would be something like mass. How much mass you have will determine the extensive property of the material.
Multicellular organisms are composed of more than one cell, with groups of cells differentiating to take on specialized functions. In humans, cells differentiate early in development to become nerve cells, skin cells, muscle cells, blood cells, and other types of cells.