The area where the two chromatid halves of a chromosome are joined is called a?

In the diagram, (1) refers to a chromatid: 1-half of two identical threadlike strands of a replicated chromosome. During cell division, the identical copies (called a "sister chromatid pair") are joined at the region called the centromere (2).

Explanation:

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One of the two identical halves of a duplicated chromosome, the two chromatids that make up achromosome are referred to as sister chromatids. The complex of DNA, proteins that makes up eukaryotic chromosomes

Following DNA replication, the chromosome consists of two identical structures called sister chromatids, which are joined at the centromere

Explanation:

the answer is d. chordata