What is the most basic unit of matter

Because there are a lot of atoms in the substances. ... The nucleus is in the centre of the atom.the electrons are around the nucleus in the electron clouds. If atoms are made of smaller parts such as electrons,why are atoms considered the basic unit of matter?

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be