Its avogadros number
No. Plain is a noun, or an adjective. The adjective plain has the adverb form "plainly."
A plain is formed when theres nothing else but grass.
plain
the European plain stretches form Pyrenees to Germany.
plain
It is called a plain.
coastal plain
Plain Plug Gauge
plain
The word 'plain' usually means self-evident, without adornment, or a land form. To use these in a sentence: SELF EVIDENT: "It was plain to the police officer that the criminal has been wounded" WITHOUT ADORNMENT: "She had a very plain and ordinary face with no distinguishing characteristics." LAND FORM: "That is a very flat plain."
Some would say 3 and others would say 4. There is the Coastal Plain, the Piedmont, and the Mountains. Some divide the Outer Coastal Plain and the Inner Coastal Plain.
vast plain on rolling hills are a vast plain full of hill, that form volcanos, lanslides, mudslides, and lava flows.