What part of the heart actually is responsible for pumping blood

Why does bubbling occur when vinegar mixed with baking soda

What is the process of pulling apart an n2 molecule nevermind i got it

The earths core is made up mainly of what 2 substances? 2. like an egg, earth has a core, a layer surrounding the core, and a thin, hard outer layer. which layers of the earth match the layers of an egg?