when body temperature rises, such as when exercising on a hot day, the dermal blood vessels will dilate, in the sweat glands begin to secrete more sweat. the invaporation of the sweat from the surface of the skin cools the body by dissipating heat.
After the Cretaceous–Paleogene extinction event wiped out the non-avian dinosaurs (birds being the only surviving dinosaurs) and several mammalian groups, placental and marsupial mammals diversified into many new forms and ecological niches throughout the Paleogene and Neogene, by the end of which all modern orders had appeared.
Bacterial conjugation is the bacterial counterpart of sexual reproduction. Also known as horizontal gene transfer, it involves the transfer of genetic material from one F+ or Hfr bacterium to another F+ or F- bacterium.
The F or fertility factor is a crucial component of the bacterial plasmid and it accounts for the development of sex pili which are important for conjugation. An F+ cells contains the F-factor incorporated into its plasmid, whereas an F- cell lacks the F-factor and therefore cannot participate in conjugation.
Conjugation between an F+ and F- cell can result in the transfer of the F-factor to the F- bacterium.
An Hfr bacterium contains F-factor incorporated into its circular genome.
