The infinitive in the sentence <em>My mother has finally learned to ride my brother's motorcycle</em> is<em> to ride </em>and functions as a A) noun.
Explanation:
An <u>infinitive</u> is the basic form a verb preceded by the particle <em>to</em>. Infinitives can act as nouns, adjectives or adverbs. As a noun, an <u>infinitive</u> can appear either as the subject of the sentence or as the direct object, like in this sentence, because it is the thing -noun or pronoun- that receives the action expressed in the verb. In this case, <em>learned </em>is the action and <em>to ride...</em> is the direct object, so it is acting as a noun.
I’d use the timeline for the first one because you’re dealing with multiple time periods and then use the compare and contrats for the second one because they seem to be comparing the two types of dinosaurs.