The pacemaker of the heart starts an electric impulse in the right to cause the atria to contract what is the pace maker of the heart.

Of four agents alpha, beta, gamma anddelta, three have to be sent together on amission. if alpha and beta cannot gotogether, beta and gamma cannot go togetherand gamma and delta cannot go together,then which of the following holds? 1. any three agents can be sent.2. alpha, delta and any one out of beta andv gamma can be sent.3. beta, gamma and any one out of alphaand delta can be sent.4. the mission is impossible.

What is the measure of ∠m? 81° 65° 53° 98° answer plz

What is the leading cause if water scarcity throughout much of the world