Sino-atrial node is called the pacemaker of our heart. Why ?

Pacemaker of heart is

SA node acts as a pacemaker of the heart because of the fact that it

Water hyacinth is called 'terror of Bengal'. Why?

Why do we call our heart myogenic ?

What is the significance of atrio-ventricular node and atrio-ventricular bundle in the functioning of heart ?

What is the significance of atrio-ventricular node and atrio-ventricular bundle in the functioning of heart ?

Why are males called heterogametic ?

Explain why gravitational force is called a centre force ?

Collenchyma is called a simple tissue. Why ?