This is the 6538th most frequent French word.
its
In French, "its" is not a word; it is English. The French equivalent is "ses" (possessive, plural) or "son/sa" (singular).
In this sentence, 'ses' is used as a possessive determiner meaning 'its,' referring to the cat's kittens.
Le chat protège ses petits avec soin.
The cat carefully protects its kittens.
Here, 'ses' signifies 'its,' referring to the leaves belonging to the tree.
L'arbre a perdu ses feuilles en automne.
The tree lost its leaves in autumn.
In this case, 'ses' indicates 'its,' referring to the toys owned by the dog.