What are the relative ages of volcanoes in a chain with a hotspot at one end?
Explain

The volcanic field is made of flood basalts that cover an area of 9,650 square miles (25,000 square km). The flows extend about 60 miles (100 km) north and south away from the arch. The youngest lava range in age from 750,000 to 900,000 years old. The oldest flows are about 2.7 million years old

Iagree the cover letter is most important it tells someone what you intend on doing

Potassium is the correct answer i believe