Final answer:
The salt content in Earth's oceans is measured in ppt (parts per thousand).
Step-by-step explanation:
The measurements that describe the salt content in Earth's oceans are C.) 25 ppt and D.) 35 ppt. Ppt stands for parts per thousand and is a unit of measurement used to express the concentration of a substance in a solution. The salt content in Earth's oceans is typically measured in ppt because it is a more accurate representation of the salt concentration compared to g/kg.
Learn more about measuring salt content in Earth's oceans