In biology, the strain is a low-level taxonomic rank used in different contexts:
In microbiology, a strain is a part of a bacterial species different from other bacteria of the same species by a minor but identifiable difference. Strains are often created in the laboratory by mutagenesis existing strains or wild-type examples of bacterial species.
In zoology, a strain corresponds to an individual or group of individuals who are at the origin of a line of descendants, sometimes called the holotype, paratypes, etc. A strain is a population of organisms that descends from a single organism or pure isolate culture. Strains of the same species may differ slightly from each other in many respects.
A strain thus consists of a group of organisms of the same species possessing certain differential traits based on their relationship; either they come from the same region, as the same watershed of a river, or they are the fruit of a particular breeding program (exists as a whole interbreeding without introductions from external sources).
All multicellular organisms use cell division for growth and the maintenance and repair of cells and tissues.
Generally, you can calculate it with this formula: df = (r-1)(c-1) where r is the number of rows and c is the number of columns.
Cellular respiration is the process that take place in the mitochondrion of a cell, it involves use of glucose from photosynthesis to produce energy in form of ATP and formation of CO2 and water. In this case, the Carbon dioxide formed passively diffuses out of the cell and Oxygen is pumped in and forces CO2 out. In this process oxygen acts as a electron acceptor.