What are the regulations of cardiac activity ??​

The cardiac cycle is a normal activity of the human heart and is regulated automatically by the nodal tissues- sinoatrial node (SA node) and atrioventricular node (AV node). The variation in the cardiac cycle results in an increase or decrease in the cardiac output.

Explanation:

The cardiac cycle is a normal activity of the human heart and is regulated automatically by the nodal tissues- sinoatrial node (SA node) and atrioventricular node (AV node). The variation in the cardiac cycle results in an increase or decrease in the cardiac output.

;)

spiders belong to a group of arachnids.

arachnids have the following traits :

they have two body parts.

they have eight legs unlike insects which have 6 legs.

they have no wings.

these traits distinguish them from insects.

the information that antonio is doubting us the statement that spiders differences are as a result of being first to evolve.

this is because the evolution of one species is independent of the other species.