Pumpkin puree, most frequently used to make pumpkin pies during the holidays, can also serve as an egg substitute in baked goods. It works especially well in dense, moist items, such as sweet breads and muffins. Trade 1/4 cup of pumpkin puree for each egg in the recipe.
Our Earth is also considered as an ecosystem on a much larger scale. When we introduce external factors such as too much carbon dioxide or methane, it destroys the balance of the ecosystem which in turn affects those who live in it. The result is global warming, water shortage, extinction of species, etc. These impacts every living thing on the planet, which includes us.
The source document for this Digest states: Natural or human-induced factors that directly or indirectly cause a change in an ecosystem are referred to as  drivers .. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely, by altering one or more direct drivers.