Detailed Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: One problem with these assignments is admixture. Many people have a highly varied ancestry. For example, in the United States, colonial and early federal history were periods of numerous interracial relationships, both outside and inside slavery. This has resulted in a majority of people who identify as African American having some European ancestors. Similarly, many people who identify as white have some African ancestors. In a survey in a northeastern U.S. university of college students who identified as "white", about 30% were estimated to have up to 10% African ancestry.
A:
What is a problem with racial assignments?