Wortino

merken: haben or sein? Perfect tense: hat gemerkt

In English: to notice; (reflexive) to remember, memorize · A2

The answer

In the Perfekt, merken takes: haben

Perfekt auxiliary
haben
Partizip II
gemerkt
Perfekt
hat gemerkt

Wortino stores one auxiliary per verb; some verbs can take both depending on the meaning.

More

Study it with cards

Wortino turns verbs into flashcards with spaced repetition: a word you struggle with comes back soon, one you know comes back less often.