Choose all of the following that accurately describe contractile characteristics of smooth muscle.

a) contraction strength is graded in proportion to the ca2+ concentration of the cytosol.
b) a basal level of ca2+ in the cytosol of some smooth muscles results in a low-level of cross-bridge activity called smooth muscle tone.
c) some inputs to a smooth muscle membrane increase contraction strength, while other inputs decrease contraction strength
d) twitch contractions are "all-or-none," meaning they are the same strength regardless of stimulus strength.
e) a membrane action potential precedes contraction in all types of smooth muscle cells.

Liquid flows at steady state at a rate of 2 lb/'s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. the liquid specific enthalpy at the inlet is 40.09 btu/lb and at the exit is 40.94 btub. the pump requires 3 btu/s of power to operate. if kinetic energy effects are negligible and gravitational acceleration is 32.174 tt/s, the heat transfer rate associated with this steady state process is most closely 1)-2,02 btu/s from the liquid to the surroundings 2)-3.98 btu/s from the surroundings to the liquid. 3)-4.96 btu/s from the surroundings to the liquid. 4)-1.04 btu/s from the liquid to the surroundings.