Breaking down the question
The question invites a stance — do you think the boundary is blurred — and demands that you Justify it. It is not enough to define the two terms; you must argue a position with reasons. The most defensible answer is a qualified yes: the boundary is indeed blurred in practice, even though the concepts have distinct analytical cores.
To justify this you need to state the conventional distinction — race as a category built around perceived physical or biological difference, ethnicity as a category built around shared culture, language, religion and ancestry — and then show why the line between them repeatedly breaks down. The two overlap empirically, both are socially constructed, and one can slide into the other through racialisation.
At 10 marks, define crisply, take a clear position, and justify it with two or three solid reasons.
How to approach it
Start with the analytical distinction so the reader knows the terms you are relating. Race conventionally refers to groups classified by supposedly inherited physical characteristics; ethnicity refers to groups sharing a common culture, language, religion, homeland or sense of ancestry. Note that ethnicity typically carries a stronger element of self-identification, while race has more often been an externally imposed classification.
Then justify the blurring. First, both are social constructions, not natural facts: modern sociology holds that racial categories have no firm biological basis and are made socially significant, just as ethnic boundaries are constructed and maintained, a point Fredrik Barth pressed. Second, the two overlap in practice — cultural markers such as religion or language are frequently treated as if they were racial, and ethnic groups become racialised when difference is essentialised and used to exclude. Third, both function as bases of group stratification and identity. Weber discussed ethnic groups in terms of shared belief in common descent. Our notes on the dimensions of stratification place both within the wider study of group inequality.
Conclude by affirming a qualified yes.
Model answer
In everyday and even scholarly usage the terms race and ethnicity are often run together, and there is good reason to hold that the boundary between them is blurred, though the concepts retain distinct analytical cores.
The conventional distinction is clear enough. Race refers to a category of people classified on the basis of supposedly inherited physical or biological characteristics such as skin colour. Ethnicity refers to a group distinguished by shared cultural attributes — language, religion, customs, a common homeland or a belief in common ancestry. A further difference is one of emphasis: ethnicity usually involves a degree of self-identification and belonging from within, whereas race has historically been an externally imposed classification used to rank and dominate.
Yet several considerations show the boundary to be genuinely blurred. First, both are social constructions rather than natural givens. Contemporary sociology rejects the idea that races are fixed biological types; racial categories are products of social definition and history. Ethnic boundaries too are constructed and actively maintained, as Fredrik Barth argued, through the marking of difference between groups rather than any fixed cultural content. If both are made rather than found, the sharp opposition between a biological race and a cultural ethnicity dissolves.
Second, the two overlap in practice. Cultural markers such as religion or language are often treated as though they signalled inborn difference, and groups defined by culture become racialised when their difference is essentialised and used to exclude — as with antisemitism or hostility towards migrant communities. What begins as an ethnic distinction can thus harden into a quasi-racial one, and vice versa. Third, both operate as bases of collective identity and stratification, generating in-groups and out-groups, boundary maintenance and unequal life chances; Weber indeed treated ethnic groups as communities held together by a belief in common descent, whether or not any objective kinship exists.
For these reasons the boundary is blurred at the level of social practice, even if analytically race foregrounds perceived physical difference and ethnicity foregrounds culture. The most accurate view is that they are overlapping, socially constructed modes of group differentiation that shade into one another, which is precisely why justified analysis keeps both concepts in view rather than treating either as self-contained.
Examiner's perspective
The examiner wants a defended position, not a paired set of definitions. The instruction Justify your answer means the marks reward reasoning: an answer that merely contrasts race and ethnicity, without arguing whether and why the line between them blurs, does not meet the demand.
Strong scripts define both terms, take a clear qualified stance, and support it with the key sociological point that both are socially constructed rather than natural, illustrating the overlap through racialisation and citing Weber on belief in common descent or Barth on boundary maintenance. Acknowledging that the concepts still have distinct analytical cores, while affirming that they blur in practice, gives the answer the nuance examiners look for at this level.