Most centipedes need to live in moist places, but a few can survive in deserts and dry grasslands. 1  These animals are found in the following types of habitat. 2  temperate. 3  tropical. terrestrial.  Terrestrial 1  Biomes. taiga.  desert or 1  dune. chaparral. 2  forest. rainforest. 3  scrub forest.  mountains.
Yeast are among the few living organisms that do not need oxygen in order to produce energy. This oxygen-independent state is called anaerobic (pronounced a-na-ROE-bik; without oxygen). During such anaerobic conditions, yeast convert carbohydratesâstarches and sugarsâto alcohol and carbon dioxide gas. This process is known as fermentation. The fermentation process of yeast is caused by enzymes, catalysts in chemical reactions similar to the digestive enzymes in the human body.
The yeast break down some of the starch and sugar present in the mixture, producing carbon dioxide. The carbon dioxide bubbles through the dough, forming many air holes and causing the bread to rise. Since oxygen is present, no alcohol is produced when the bread is rising. When the bread is baked, the air holes give the bread a lighter texture. In recent times, yeast have been used to aid in the production of alternative energy sources that do not produce toxic chemicals as byproducts.