The way genes determine traits with cells is now well understood. This has opened up a new field of study called genetic engineering, through which organisms can be modified or engineered to possess new traits. It is common practice in the field of genetic engineering to remove a gene from one organism and insert it into the genome of another. It is a challenging task, but many examples of genetically modified organisms have been produced in both the plant and animal domains. Since genes from one organism can be inserted into the genome of a completely different organism, which statements below are conclusions that can be made from this observation? Select all that apply.

A. All forms of life have DNA in their nucleus.

B. In cells, traits are the result of proteins, and protein production is controlled by genes.

C. The molecular basis of inheritance is universal in all forms of life.

D. By changing one letter in the genetic code, the entire gene changes.