Final answer:
The items of material culture that are disappearing due to increased trade and contact with the outside world include traditional cookware, clothing, and jewelry, which are replaced by mass-produced trade goods.
Step-by-step explanation:
As the "Y" people, which could be any society being referenced as an example, have more contact with the outside world and access to trade goods, there are several items of material culture that may be disappearing. Traditional handmade items such as clay cookware, and animal-skin clothing are often replaced by metal cooking implements and European textiles. Local artisanal skills used to create jewelry and adornments may decline as imported goods become more prevalent and affordable. Changes in material culture are not just confined to physical objects but also include the substitution of traditional lifestyles and practices with those influenced by external cultures. As trade increases, local cultures often adapt to or adopt the ways of more dominant or influential cultures, leading to a homogenization of material culture across different societies.