What are logous Chromosomes (I've checked google, but still don't understand it)?

The question is a little odd. I'd say that an "allele" is a version of a gene. Sometimes, you might inherit the exact same sequence for a particular gene from your mother and your father, and sometimes, the copy you go from your mother is a bit different form the copy you got from your father. In the first case, you are zygous for that one allele of that gene, in the second case, you are heterozygous for those two alleles of that gene.