Are these factors of production: gases from the air, fruits from trees...If so which factor of production?

Question

Also, what about factories?

Answer 1

Gases from air and fruits from trees would be classified as physical capital.

Answer 2

anything you can use to help produce a product that can be sold for a non-zero price is a factor of production.   So, yes, the air contains oxygen and nitrogen.  both are useful in a variety of production applications.  the obvious example is that oxygen is required to burn something.  Burning coal or wood produces heat, which can boil water and create steam which is used to power plants and equipment.   so access to air with sufficient oxygen to burn something is a factor of production.  

Fruits from the trees are often used in various recipies, and the acid from fruits is also used for non-food applications.