Answer:a) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates.
Explanation:
An ancestor - An earlier type of a species at any distant time — a progenitor.
A tetrapod is any vertebrate with four limbs. It includes any vertebrate (such as birds or snakes) that have evolved from early tetrapods — especially all members of the superclass Tetrapoda.
The presence of bones that support the appendages in Lobe – fin fish were found to be similar to the categorical skeletal supports found in the limbs of sample tetrapods. The sub class crossopterygii includes the Lobe – fin fish, which is seen as one of the recent common ancestor of living tetrapod today.
only about 3% because all of the other water would have to be filtered incorrect to be safe to drink so the student was incorrect in saying that there was water directly for humans to drink
