Final answer:
Proto-Dravidian is believed to be the ancestor of Dravidian languages, but the exact number of Dravidian languages is disputed.
Step-by-step explanation:
Proto-Dravidian is believed to be the ancestor of the Dravidian languages spoken in southern India today. However, it is important to note that there is no consensus among linguists regarding the exact number of Dravidian languages. Some experts estimate that there are 21 Dravidian languages, while others argue that there are fewer or more. Therefore, the statement that Proto-Dravidian gave rise to 21 Dravidian languages is not entirely accurate.