The pacemaker of the heart is situated in:

Where is the pacemaker located?

The human heart is derived from which germ layer?

When the heart of a frog is removed from the body,it continues to beat for some time. Select the correct statement$(s)$ from the following:
$(i)$ The frog is a cold-blooded animal.
$(ii)$ The frog does not have a heart-based circulatory system.
$(iii)$ The heart has myogenic properties.
$(iv)$ The heart is self-excitable.

Cardiac output signifies

What is a pacemaker?