Context: Like all the Romance languages, Catalan verbal inflection is more complex than the nominal. Suffixation is omnipresent, whereas morphological alternations play a secondary role. Vowel alternances are active, as well as infixation and suppletion. However, these are not as productive as in Spanish, and are mostly restricted to irregular verbs.

Question: What is Catalan verbal inflection ?
Answer: more complex

Question: What plays a primary part in Catalan?
Answer: Suffixation

Question: What plays a secondary part in Catalan?
Answer: morphological alternations

Question: How are vowel alternances in Catalan?
Answer: active