Question

Strolling tourists fill the streets of Rome. Identify the type of verbal used in the sentence above and the word it modifies. gerund: “tourists” infinitive: “streets” gerund: “Rome” participial: “tourists”

Answer 1

D-participial: “tourists”

Answer 2

The Verbal here is :"strolling" - the only other verbal form here is the inflected verb, "fill".

(so we reject the options:
infinitive: “streets”
participial: “tourists” )

this verbal modifies "tourists": the tourists are strolling - it has a function of an adjective.