Answer:
i think they both attach different surfaces together
they both stick
The infinitive phrase in this sentence is to speak clearly, and it is used as a subject of the sentence. What/who is essential to being understood? To speak clearly.
The answer is C. Interrogative/Nominative
the principal and most anterior part of the brain in vertebrates, located in the front area of the skull and consisting of two hemispheres, left and right, separated by a fissure. It is responsible for the integration of complex sensory and neural functions and the initiation and coordination of voluntary activity in the body.