Each axis on a graph should be: equal numbered labeled vertical

What was the land like over 500 million years ago? what was under the sea?

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks

Pentane with molecular formula c5h12, exists in three isomeric forms. one shows linear carbon chains, another has one -ch3 groups present on the third carbon atom, and the third has two -ch3 groups present on the second carbon atom. what types of isomers are these? a. geometric isomers b. structural isomers c. halotropic isomers