Final answer:
Genes are found in the nucleus because of the presence of chromosomes, which are DNA strands wrapped around proteins.
Step-by-step explanation:
The fact that genes are found in the nucleus and not in the cytoplasm can be explained by the presence of chromosomes in the nucleus.
Chromosomes are strands of DNA that contain genes.
They are structures made of DNA tightly wrapped around proteins.
In eukaryotic cells like human cells, the chromosomes are located in the nucleus, while in prokaryotic cells like bacteria, the DNA is present in a region of the cytoplasm called the nucleoid.