Library.

“Carbon is an essential building block of life.”

Carbon is a core structural element of known life. Scientific sources consistently show that carbon forms the backbone of the main biological macromolecules because it can make stable, complex bonds in ways crucial to biochemistry. The claim is accurate as stated, though it refers to life as known on Earth and does not imply carbon is the only essential element.

“The ocean stores more carbon than the atmosphere.”

The scientific evidence shows the ocean holds far more carbon than the atmosphere. Standard carbon-cycle estimates put ocean carbon at roughly 38,000 gigatons of carbon, compared with about 800-900 gigatons in the atmosphere. Caveats about deep-ocean storage or exchange rates do not change the basic comparison the claim makes.