Which of the following is NOT a characteristic of embryonic stem cells?

Embryonic stem cells are unique in several ways that distinguish them from other types of cells. One of the defining characteristics of embryonic stem cells is their pluripotency, meaning they have the ability to differentiate into nearly any cell type in the body. Additionally, they possess a self-renewal capability, allowing them to replicate themselves indefinitely in culture.

The statement about embryonic stem cells existing inside the adult body is not accurate because, typically, embryonic stem cells are derived from the inner cell mass of an early embryo, specifically during the blastocyst stage. Once an organism develops, the adult body contains different types of stem cells, such as adult stem cells, but not embryonic stem cells themselves.

In contrast, the ability to form various other cell types and the presence in early embryos accurately describe embryonic stem cells. Hence, identifying the claim regarding their existence in the adult body is correct, as it directly contrasts with the fundamental nature of embryonic stem cells.