With the mapping of the human genome and the development of karyotypes to predict genetic abnormalities, there is a growing need for researchers in the field of

DNA is located in the nucleus.

Explanation:

let's dissect each statement one by one

Nucleotides form a helical structure that is called a gene.

Nucleotides do indeed form a helical structure along with a phosphate group and a sugar to form DNA a gene is a small section of DNA so the first statement is not great

Genes combine to form structures called nucleotides.

As aforementioned nucleotides build DNA, genes are a section of DNA, this statement is false

Chromosomes create genes.

This statement is actually backwards

DNA is located in the nucleus.

We can find DNA inside the nucleus, somthing we learn in eighth grade