A researcher believes that human languages originally originated directly from birds and primates, because if we re-examine modern human languages, we can see how human interaction has evolved from the ancient communication model system of birds and other primates. Here, he claims, from birds, we get the melodic part of the language; from other primates, we get the practical content part of the language. At some point in the past 100,000 years, these capabilities eventually Evolved into the human language we know today. Which of the following premise does the above conclusion need to be based on? ['There is more similarity between human communication and other animal communication than we generally think.', 'The human language contains two different levels: the expression level related to the variable structure of the sentence and the lexical level to express the core content of the sentence.', 'Human language communication has changed little in the past and present.', 'Birds and mammals other than humans have their own language of communication.']