A.I am protect my plants.  --> I protect my plants.

I am protect our nature. --> I protect our nature.​

 I am protect my sister. --> I protect my sister.

​=> Corrected: The sentences are corrected grammatically.

B.  How old are you? (Correct)

I am 10 years old. (Correct)​

Whose she is? --> Who's she?

​=> Corrected: The sentence is corrected grammatically.​