Context and question: Bacteria often attach to surfaces and form dense aggregations called biofilms or bacterial mats. These films can range from a few micrometers in thickness to up to half a meter in depth, and may contain multiple species of bacteria, protists and archaea. Bacteria living in biofilms display a complex arrangement of cells and extracellular components, forming secondary structures, such as microcolonies, through which there are networks of channels to enable better diffusion of nutrients. In natural environments, such as soil or the surfaces of plants, the majority of bacteria are bound to surfaces in biofilms. Biofilms are also important in medicine, as these structures are often present during chronic bacterial infections or in infections of implanted medical devices, and bacteria protected within biofilms are much harder to kill than individual isolated bacteria.
How extent can biofilm be?
Answer: up to half a meter in depth
Context and question: Genes with a most recent common ancestor, and thus a shared evolutionary ancestry, are known as homologs. These genes appear either from gene duplication within an organism's genome, where they are known as paralogous genes, or are the result of divergence of the genes after a speciation event, where they are known as orthologous genes,:7.6 and often perform the same or similar functions in related organisms. It is often assumed that the functions of orthologous genes are more similar than those of paralogous genes, although the difference is minimal.
What are genes with a most recent common ancestor called?
Answer: homologs
Context and question: From 2000 to 2009, the AFL had its own developmental league, the af2. The AFL played 22 seasons from 1987 to 2008; internal issues caused the league to cancel its 2009 season, though the af2 did play. Later that year both the AFL and af2 were dissolved and reorganized as a new corporation comprising teams from both leagues, and the AFL returned in 2010. The Arena Football League has its headquarters in Chicago, Illinois.
When was the first AFL season played?
Answer:
1987