* Chromosomes are located in the nucleus of a cell. They contain the genetic material (DNA) that carries instructions for building and maintaining the organism.

* Mitochondria are organelles found outside the nucleus. They are responsible for energy production within the cell and have their own separate DNA.

Here's how traits are determined:

1. Genes on chromosomes: The instructions for specific traits are encoded within genes, which are segments of DNA on chromosomes.

2. Inheritance: An organism inherits one set of chromosomes from each parent, resulting in pairs of chromosomes. Each chromosome in a pair carries a gene for the same trait, but the versions of those genes (alleles) can be different.

3. Expression: The combination of alleles inherited from both parents determines the expression of a trait. This is called genotype (the genetic makeup) and phenotype (the observable trait).

Mitochondrial DNA (mtDNA) plays a role, but not in the same way as nuclear DNA:

* mtDNA inheritance: mtDNA is inherited only from the mother.

* mtDNA function: mtDNA primarily codes for proteins involved in energy production within mitochondria.

* mtDNA and traits: While mutations in mtDNA can cause certain diseases, they typically don't directly determine major traits like eye color or height.

In summary: Chromosomes contain the primary genetic information determining most traits, while mitochondria play a crucial role in energy production and have their own separate DNA, which can influence certain traits.