Why do production possibilities curves only compare two different goods or services?

The layers of earth are based on what two sets of characteristics?

Venezuela’s economy relies most heavily on which of the followingvenezuela’s economy relies most heavily on which of the following? a. oil reserves in places such as the eastern llanos b. cattle ranching in the grasslands c. fertile farmland in the andean highlands d. coffee plantations in mountainous areas

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