Question

Какой корень в словах-собачий,собака, собачатня,собачёнок

Answer 1

Корни -собач- и собак-  - чередование -ч- и -к-.

Answer 2

Root in the Words "Собачий," "Собака," "Собачатня," "Собачёнок"

The root in the words "собачий," "собака," "собачатня," and "собачёнок" is "собак".

This root is common in all the words and is related to the concept of a dog or dogs.