The most prominent roles of mitochondria<span> are to produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration, and to regulate cellular metabolism. The central set of reactions involved in ATP production are collectively known as the citric acid cycle, or the Krebs cycle</span>
<span>Ancient cultures knew that unseen energy flows through all living things. Reiki is a system of healing that channels this energy by placing the hands. In recent scientific experiments, medical doctors are studying the correlation between this energy and the functioning of the immune system.</span>
The removal of the producers would cause the collapse of the entire food web. Primary consumers or herbivores, which feed on producers directly, would die off.
They are both important because mechanical has to do with physical - cause mechanical means physical, so chewing your mouth is physical (you break your food into smaller pieces physically). And then chemical digestion is when food and saliva mix together. They happen when breaking down food into nutrients - enzymes. Enzymes are important for that process, because they make a nutrient.
Hope this helps!!