Что это? Кто это?
Ask кто это? when you talk about animate objects (that denotes persons or animals)
Ask что это? when you talk about inanimate objects (that denotes objects)
Notes:
1) Read more about the difference between animate and inanimate objects here - https://www.ruspeach.com/learning/2155/
2) мой, моя - are posessive pronouns, they change their endings because of the gender of the noun they go with. (read more about it here - https://www.ruspeach.com/learning/3371/)
Кто это?
[kto èhta]
- Who is this?
Это моя мама.
[èhta maja màma]
- This is my mom.
Это мой папа.
[èhta moj pàpa]
- This is my dad.
Ask что это? when you talk about inanimate objects (that denotes objects)
Что это?
[shto èhta]
- What is this?
Это мой стул.
[èhta moj stùl]
- This is my chair.
Это моя книга.
[èhta mayà knìga]
- This is my book.
Notes:
1) Read more about the difference between animate and inanimate objects here - https://www.ruspeach.com/learning/2155/
2) мой, моя - are posessive pronouns, they change their endings because of the gender of the noun they go with. (read more about it here - https://www.ruspeach.com/learning/3371/)