Cardiac outputIn cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols , , or , is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by a single ventricle of the heart, per unit time (usually measured per minute). Cardiac output (CO) is the product of the heart rate (HR), i.e. the number of heartbeats per minute (bpm), and the stroke volume (SV), which is the volume of blood pumped from the left ventricle per beat; thus giving the formula: Values for cardiac output are usually denoted as L/min.
Fancy ratThe fancy rat (Rattus norvegicus domestica) is the domesticated form of Rattus norvegicus, the brown rat, and the most common species of rat kept as a pet. The name fancy rat derives from the use of the adjective fancy for a hobby, also seen in "animal fancy", a hobby involving the appreciation, promotion, or breeding of pet or domestic animals. The offspring of wild-caught specimens, having become docile after having been bred for many generations, fall under the fancy type.
Obstetrical dilemmaThe obstetrical dilemma is a hypothesis to explain why humans often require assistance from other humans during childbirth to avoid complications, whereas most non-human primates give birth unassisted with relatively little difficulty. This occurs due to the tight fit of the fetal head to the maternal birth canal, which is additionally convoluted, meaning the head and therefore body of the infant must rotate during childbirth in order to fit, unlike in other, non-upright walking mammals.
