* Genes are indeed the fundamental units of inheritance. They carry the instructions for building and maintaining an organism.

* Genes are located on chromosomes. Chromosomes are long strands of DNA that carry the genetic information.

However, chromosomes are not the only units of inheritance. There are other factors that influence inheritance, such as:

* Epigenetics: Chemical modifications to DNA that can alter gene expression without changing the DNA sequence.

* Mitochondrial DNA: Mitochondria, the powerhouses of cells, have their own DNA that is inherited from the mother.

* Extrachromosomal DNA: Some organisms carry genetic information on small circular DNA molecules called plasmids.

Therefore, while genes on chromosomes are the primary units of inheritance, other factors also play a crucial role.