Are all three types of RNA coded by the same genes?
There are different types of genes for encoding three types of RNA. Protein coding genes are transcribed by RNA polymerase II to yield mRNA. Ribosomal RNA (rRNA) are transcribed by RNA polymerase I. Likewise, transfer RNA (tRNA) are transcribed by polymerase III.
All cells in a multicellular organism possess the same genes. However, different cell types express different genes. Indeed, that is what makes the cells different. During development, cells are directed towards particular lineages, each lineage activating particular sets of genes, genes that confer a particular identity on a cell and the appropriate properties.
Why are most of your traits are not inherited according to the for a simple mono hybrid cross in which we look at character that is coded for by only one dominant allele and one recessive allele?
If your question is "why is there almost always independent segregation when genes can be on the same chromosome and therefore a bunch of genes must move with the same chromosome (i.e. dependently)?", then the answer is that genes on the same chromosome can segregate into different gametes by genetic recomination, i.e. cross-over during meiosis prophase I.
What is heterozygous? Your inherited characteristics are determined by your genes. Zygosity refers to the similarity of genes for a trait in an organism. If both genes are different, the organism is heterozygous (hetero = different) for that trait. If both genes are the same, the organism is homozyous (homo = same).
It's not gene pools that have a frequency, but alleles that have a frequency in the gene pool. Alleles are "rival" variants for the same gene. For instance, if hair colour is coded by one gene, then brown hair may be allele A for that gene, while blonde hair is allele B for the same gene. Imagine people as being packages of genes, each containing two full sets of genes (humans are diploid, so we…