What does the oxygen contains more in the nucleus

The first element on the periodic table of elements is carbon. a. true b. false

How to convert a density of 0.791g/cm3 to lb/ft3

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?