Why is my and cat combined?
My cat = kucing saya = kucingku
What is kucingku like the right answers says it is?
Kucingku is informal. But it should be accepted.
why does my cat have a dog?
It's not the cat who owns the dog. Imagine Andi has a dog and Tini has a cat. Then, Tini sees her cat chasing Andi's dog.
Tini says, "Kucing saya mengejar anjingnya". -nya is back to Andi.
for a moment i thought the cat had a dog then i realized its probably another person's dog
Is "... anjingnya dia" acceptable?
"... anjingnya dia" is not an effective statement but should be accepted.
Formally, it's incorrect.
Why the hell is it anjing dia? Why not anjingnya? What are we speaking bahasa pasar?
It's "anjingnya" now.
For "bahasa pasar": I don't know what Duolingo team want. Sometimes they are very strict with Standard form (bentuk baku) but sometimes they combine the lesson with Non-standard (tidak baku).
Perhaps it is a Tiger, not cat.
kucing lebih kuat dan pintar