This is the 8886th most frequent Portuguese word.
arqueológicos
"Arqueológicos" means "archaeological" in English, relating to the study of ancient artifacts and cultural remains.
Here, 'arqueológicos' is used as an adjective describing the type of sites ('sítios'). It conveys the idea that they are related to archaeology.
Os sítios arqueológicos na região atraem muitos turistas.
The archaeological sites in the region attract many tourists.
In this sentence, 'arqueológicos' describes the nature of studies ('estudos'), specifying that they pertain to the field of archaeology.
Estudos arqueológicos revelaram informações sobre civilizações antigas.
Archaeological studies revealed information about ancient civilizations.
'Arqueológicos' functions as an adjective explaining that the projects are connected to archaeology and aimed at preservation efforts.