Which of the following correctly distinguishes exotoxins from endotoxins?

Exotoxins are lipid molecules, while endotoxins are proteins.

Exotoxins are secreted outside of bacterial cells, while endotoxins are found within bacterial cells.

Exotoxins are exclusively produced by gram-negative bacteria, while endotoxins are produced by gram-positive bacteria.

Exotoxins are resistant to enzymatic degradation, while endotoxins are easily broken down.