Answer:
Adverb: Often
Adjective: Much
Step-by-step explanation:
The above are correct.
An adverb is known to be a word or phrase that actually modifies or explains a verb, adjective, word group, or even other adverb. Adverbs are used to express manner, circumstance, time, degree, etc.
An adjective is a word that modifies or qualifies a noun or a pronoun in a sentence.
From the above sentence, we discover that the adverb "often" is modifying the the adjective "much". The adverb "often" explains how frequent they eat "much".