Sorry but that makes absolutely no sense to me
OK. So, at a certain place on chromosome 1, ALL of us have the same gene (hypothetically, the gene that decides whether we have pink or blue hair, because it codes for pigment proteins). All of us have this hair colour gene on chromosome 1, that decides our hair colour, but we don't necessarily have exactly the same DNA sequence at this gene; some of us have the sequence that codes for a blue-pigment protein, while some of us have the sequence that codes for a pink-pigment protein. So, some of us have a blue allele and some a pink allele, because we have different VARIATIONS/forms of the gene/trait.
Then, we all have two copies of the chromosome - if we have two blues, we have blue hair, two pinks, we have pink hair, (homozygous), and one of each? Well obviously blue is the better colour
, so blue must be dominant, and the heterozygote will have blue hair.
Naturally it doesn't actually work like this, but hope dat makes some sense...
Is an intron the same as the non-coding section of a gene/DNA molecule?
Yep, because it gets cut out of the mRNA sequence, it's never translated, so it doesn't code for amino acids, so it's a non-coding section