1.whereas owners of condominium apartments have free and clear title to their dwellings, owners of cooperative apartments have shares in a corporation that owns a building and leases apartments to them.

在上句中their 和them 分别指什么？

2.According to a recent poll, owning and living in a freestanding house on its own land is still a goal of a majority of young adults, like that of earlier generations.

答案说此句中that无明确指代对象，为什么？