Why do scientists study Antarctica

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?

Why is the huronian supergroup rock formation particularly interesting to scientists? because it looks like a cross-section of a giant, stone encyclopedia because it formed during the period when oxygen began to accumulate in the atmosphere because it contains unusually large amounts of oxygen and sulfur because it dramatically altered the planet's development when it first formed

Which soil layers comprise the topsoil? o horizon a horizon b horizon c horizon