**Colibri **answered most of your question, but regarding 47 chromosomes…
Depends on how you do the counting. Most cells are diploid (they have chromosomal pairs), so you can’t have an odd number. Gamete cells are haploid (the chromomsomes are unpaired), and so they can have odd numbers. I usually think in terms of haploid number (23, for humans) to avoid the confusion. An odd chromosome number in a diploid cell can occur, but is usually considered an abnormality-- like people with Downs syndrome which is caused by an extra chromosome 21 in humans. People with Down Syndrome do have 47 chromosomes. There are also people with a diploid number of 45-- for example, girls with only one X chromosome. You won’t find any individuals with only a Y chromosome, though. Just another exapmle of why females are superior to males, I guess.
Not all species have only diploid or haploid cells, btw. There are lots of species, expecially plants, that have polylploidal cells (more than 2 of each chromosome).
Here’s an interesting article which discusses the House Mouse Mus musculus, which has subspecies that vary in diploid chromosome number between 22 and 40 but still are part of the same biological species.
