Answer:
This statement is true.
Step-by-step explanation:
Ethnicity means belonging to a particular social group. It includes the groups' cultural factors such as nationality and language, amongst others.
Culture refers to the characteristics and knowledge of a certain group which includes habits, religion, language and customs, amongst others.
In this case it is true that people can generally only have one ethnicity such as being Spanish but can belong to multiple cultures such as having different traditions besides the Spanish one, for example.