What factor made southeast asia one of the world’s great geographic crossroads?

Physical features of central america look at the map above which of the following is true

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 two following best identify the central themes of this speech in the passage the man in the arena