Final answer:
The streams on either side of the great divide flow in opposite directions. This divide separates watersheds leading to different oceans, and streams on each side head toward the respective oceans.
Step-by-step explanation:
The statement that best describes the streams on either side of the great divide is: a) They flow in opposite directions. The great divide, often referring to the Continental Divide of the Americas, is a natural boundary that separates watersheds where water flows to different oceans. On one side of the divide, streams will flow toward one ocean, while on the other side, they will flow toward another ocean.
As for how rivers and streams behave, rivers and streams are dynamic systems that start narrow and fast-moving at their source, and as they flow away from the source, they widen and slow down. These waters incorporate tributaries and carry sedimentation, affected by the gradient decrease and volume increase as tributaries unite.