<span>Unidirectional flow in the heart is ensured because the heart contains valves that prevent backflow.
These valves keep the flow of the heart going in one direction (hence the name "unidirectional").</span>
Answer:
Crossing over is a biological occurrence that happens during meiosis when the paired homologs, or chromosomes of the same type, are lined up. Hope this helps :)
Explanation:
It’s not B or C. I want to say A but I’m not 100% sure
I think the answer would be mid-noon.
