Why is the sahara desert considered an ecosystem

The Sahara Desert is considered an ecosystem because it is a community of living organisms, along with non living parts of the environment.

Where are the statements so i can ?

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen