Gap junctions in the intercalated discs allow impulses to be spread across the heart more quickly. This is because gap junctions allow particles/signals to pass through, thus making cells with gap junctions more able to interact.
One more thing—you posted this in the physics section rather than biology.
The answer to the question
Answer:
man will move in opposite direction with speed

Explanation:
As we know that man is lying on the friction-less surface
so here net force along the surface is zero
so if we take man + stone as a system then net change in momentum of this system will become zero
so here we have


here we have



Explanation :
It is given that,
Diameter of the coil, d = 20 cm = 0.2 m
Radius of the coil, r = 0.1 m
Number of turns, N = 3000
Induced EMF, 
Magnitude of Earth's field, 
We need to find the angular frequency with which it is rotated. The induced emf due to rotation is given by :




So, the angular frequency with which the loop is rotated is 159.15 rad/s. Hence, this is the required solution.
Yeah, it's every state. Atoms need a certain quanta of energy to jump to each state of energy, and therefore change state depending on how much energy is absorbed and/or released. This applies to all states of matter.