Some of these are not examples of homeostasis: (circle those that are not)
Various mechanisms to keep the pH of the blood within a narrow range

The human ciculatory system can be thought of as a closed system of interconnecting pipes through which fluid is continuously circulated by two pumps the two pumps the right and left verticles of the heart, work as simple two-stroke force pumps. The muscles of the heart regulate the force by contracting and relaxing. the contraction (systole) lasts about 0.2s and a complete systole/diastole (contraction/relaxation) cycle lasts about 0.8s. For flood pressures and speeds in the normal range. the volume flow rate of blood through a blood vessel is directly proportional tot he pressure difference over a length of the vessel and to the fourth power of the radius of the vessel. The total mechanical energy per unit volume of blood just as it leaves the heart is E//V=rhogh+P+rhov^(2) Q. Which of the following is a way to achieve approximately a 45% increase in the volume flow rate of blood through a blood vessel?

Two circles of radius 4 units and 3 units are at some distance such that the length of the transverse common tangent and the length of their direct common tangent are in the ratio 1 : 2. What is the distance between the centres of those circles.