How many types of quarks are there and how many types of antiquarks?

The two required components for a generator

Selma made a diagram to compare convection and radiation. which label belongs in the area marked x? must involve temperature differences between substances or objects only occurs when molecules are in direct contact involves the movement of fluids based on density differences can occur where there is little or no matter

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?