At the beginning of systole, when ventricular pressure exceeds atrial pressure, the AV valves close. However, initially the semilunar valves also remain closed since ventricular pressure is still not sufficiently strong enough to force them open (consequently at this point in the cardiac cycle there is no blood flow into or out of the ventricles). This phase is known as . A) isovolumetric relaxation (phase 4)
B) isovolumetric contraction (phase 2)
C) ventricular ejection (phase 3)
D) ventricular filling (phase 1)

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )

= initial pressure

= final pressure = 2

= initial volume

= final volume = /4

= initial temperature = 20 c = 20 + 273 = 293 k

= final temperature = ?

using the equation