Transform the word in brackets so that it fits the text lexically and grammatically. Write the answer in capitals without gaps.

In Moscow, there are approximately 35,000 dogs living on the streets. Some of these _________________ animals were born there. Others are just __________________ pets that have been abandoned by their owners. For many dogs the city may be a _______________ place to live in. However, scientists were surprised to find out how ____________ \(EASY\) some animals can adapt to urban life. Some dogs have even learnt to use the city’s metro system! We still don't know how the dogs find out when to get off the train. One_____________ is that they use their excellent sense of smell to recognise the scents of their favourite destinations. Another idea is that they are able to remember the design of ____________stations and find the station they need.