What source type fits this quotation Chewing licking and sucking are extremely widespread mammalian activities which in terms of casual observation have obvious similarities with speech?

The quotation is: "Chewing, licking and sucking are extremely widespread mammalian activities, which, in terms of casual observation, have obvious similarities with speech." (MacNeilage, 1998). - Since it talks about teeth, tongue and lips, it would be from the physical adaptation source in the selections you were given.