Even less fortunate was the extension of this type of thinking.....


Senior Member
This text ia from TOEFL.
Even less fortunate was the extension of this type of thinking to include animals as well as plants. This resulted in the “biome,” a combination of coexisting flora and fauna. Though it is true that many animals are strictly associated with certain plants, it is misleading to speak of a “spruce-moose biome,” for example, because there is no internal cohesion to their association as in an organism.
What function does 'to' perform?
  • Keith Bradford

    Senior Member
    English (Midlands UK)
    It creates an infinitive from the root verb "include". The only verb-forms that can function as nouns are an infinitive or a present participle. In this sentence an infinitive is required.


    Senior Member
    English - South-East England
    The meaning is something like 'so that', purpose:

    This kind of thinking was extended so that it included . . .

    But also, we extend something to a new destination. So it could also be thought of like the preposition: the thinking was extended to the inclusion of . . .