Ответ:Ответ:1) Is climate changing? Yes,it is.

2)Are tigers becoming extinct? Yes, are they.

3)Aren’t you talking to Billy? No, I am not.

4)Is that female bear protecting her baby? Yes, it is.

5)Are we learning new vocabulary? Yes, we are.

6) Are your fiends running in the park now? No , they aren’t

7) Is Jack looking for his book? No, he isn’t.

Объяснение: глагол to be + сущ/местоимение + основной глагол