I don't completely understand what you mean by "pieces". Humans have 23 pairs of chromosomes. That means they have 46 "pieces". 23 come from each parent. DNA is concentrated into little rods called chromosomes. There are two "pieces" on each chromosome.
The exact number of genes contained in the human genome are still unknown, the current estimate is usually around 25,000 genes.
Nucleus
The nucleus of a cell is what gives it its structure. There are 92 pieces of DNA in the nucleus of a cell.
23 Pairs of chromosomes or 46 chromosomes.
Yes it is true. Mammalian (e.g. human) red blood cells have no nuclei. This enables them to be smaller, allowing them to carry more oxygen around the body.
all cells that have a nucleus are eukaryotic.
Nucleus
The nucleus of a cell is what gives it its structure. There are 92 pieces of DNA in the nucleus of a cell.
None! A nucleus is in a cell there are no cells in a cell
23 Pairs of chromosomes or 46 chromosomes.
Yes it is true. Mammalian (e.g. human) red blood cells have no nuclei. This enables them to be smaller, allowing them to carry more oxygen around the body.
they have only one nucleus
Nuclei do not contain cells, cells contain nuclei (normally, one nucleus per cell).
all cells that have a nucleus are eukaryotic.
About 35,000 genes per body cell. Note: sex cells differ.
Not all cells have a nucleus. Also nuclei is plural many cells only have one nucleus. Generally cells that have a nucleus have DNA in it. It is suspected that originally the nucleus of cells had RNA instead of DNA and it is suspected that some cells still have RNA in their nucleus. A number of viruses use RNA instead of DNA.
Multicellular organisms do not have a nucleus; rather they have many nuclei. Most cells in an organism have a nucleus (with a few exceptions like red blood cells).
Cells that do not contain a "true" nucleus are called prokaryotes. Sometimes eukaryotic cells are anucleate(no nucleus) when mature. Erythrocytes (red blood cells) in mammals are an example of eukaryotic cells that do not contain a nucleus when mature.